Can a CPU support more ram, than specified by intel?

Solution 1:

That CPU is indeed not able to address more than 32 GB RAM.
The extra RAM will not be usable.
It will simply not be visible/usable by any OS.

So buying it with the larger RAM option would be a waste of money.

Why is it being sold like that anyway?
Without asking the vendor this is only a guess, but...
Plenty of people are not technically savvy enough to notice that they are not using the whole RAM they paid for.
Even those that do realize what is going on may not take further action (it is too much effort to do or they are too embarrassed to admit they fell for this).
Only a small number will actually complain/request a refund.
The vendor probably makes enough of a margin on the >32GB version to offset any returns/complaints by unsatisfied customers.

And the vendor doesn't really do anything wrong.
All the information is in the specifications. The vendor doesn't claim the RAM >32GB is actually useful.
You are probably not even entitled to a refund because the product is not misrepresented at all.

Solution 2:

To answer the overarching question: "Intel Ark is usually right, but not always."

Some specifications from any product sheet can be considered to be "usual-case," whereas external factors can limit or increase performance. For example, the Intel i7-8550U lists its base clock speed as 1.80GHz. But, one can exceed this limit by overclocking with supporting hardware.

To answer the specific question about the Intel i7-8550U, some Intel 8th Generation U-series processors may support 64GB of memory natively.[1]

Quoted from [1], Section 2.1.1.1, Table 2-5:

Supported DDR4 Non-ECC SODIMM Module Configurations (H/U-Processor Lines)

Raw Card Version DIMM Capacity DRAM Device Technology DRAM Organization # of DRAM Devices # of Ranks # of Row/Col Address Bits # of Banks Inside DRAM Page Size
E 32 GB 16 Gb 2048M x 8 16 2 17/10 16 8K

By using two such 32GB DIMMs, 64GB system memory can be achieved.

Also, to see it in practice, here is the exact hardware configuration you are referring to detecting and utilizing 2x32GB system memory:

Environment is one of your aforementioned hardware devices running Debian Linux

root@debian:~# dmidecode -qs system-product-name
FW6E

root@debian:~# uname -a
Linux debian 5.10.0-0.bpo.3-amd64 #1 SMP Debian 5.10.13-1~bpo10+1 (2021-02-11) x86_64 GNU/Linux

CPU is i7-8550U

root@debian:~# dmidecode -qs processor-version
Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz

Memory is 2x32GB DIMMs

root@debian:~# dmidecode
Handle 0x0035, DMI type 16, 23 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: None
        Maximum Capacity: 64 GB
        Error Information Handle: Not Provided
        Number Of Devices: 4

Handle 0x0036, DMI type 17, 40 bytes
Memory Device
        Array Handle: 0x0035
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 32 GB
        Form Factor: SODIMM
        Set: None
        Locator: ChannelA-DIMM0
        Bank Locator: BANK 0
        Type: DDR4
        Type Detail: Synchronous Unbuffered (Unregistered)
        Speed: 2667 MT/s
        Manufacturer: Kingston
        Serial Number: C792668A
        Asset Tag: 9876543210
        Part Number: 9905744-067.A00G    
        Rank: 2
        Configured Memory Speed: 2400 MT/s
        Minimum Voltage: 1.2 V
        Maximum Voltage: 1.2 V
        Configured Voltage: 1.2 V

Handle 0x0037, DMI type 17, 40 bytes
Memory Device
        Array Handle: 0x0035
        Error Information Handle: Not Provided
        Total Width: Unknown
        Data Width: Unknown
        Size: No Module Installed
        Form Factor: Unknown
        Set: None
        Locator: ChannelA-DIMM1
        Bank Locator: BANK 1
        Type: Unknown
        Type Detail: None

Handle 0x0038, DMI type 17, 40 bytes
Memory Device
        Array Handle: 0x0035
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 32 GB
        Form Factor: SODIMM
        Set: None
        Locator: ChannelB-DIMM0
        Bank Locator: BANK 2
        Type: DDR4
        Type Detail: Synchronous Unbuffered (Unregistered)
        Speed: 2667 MT/s
        Manufacturer: Kingston
        Serial Number: C2A27761
        Asset Tag: 9876543210
        Part Number: 9905744-031.A00G    
        Rank: 2
        Configured Memory Speed: 2400 MT/s
        Minimum Voltage: 1.2 V
        Maximum Voltage: 1.2 V
        Configured Voltage: 1.2 V

Handle 0x0039, DMI type 17, 40 bytes
Memory Device
        Array Handle: 0x0035
        Error Information Handle: Not Provided
        Total Width: Unknown
        Data Width: Unknown
        Size: No Module Installed
        Form Factor: Unknown
        Set: None
        Locator: ChannelB-DIMM1
        Bank Locator: BANK 3
        Type: Unknown
        Type Detail: None

Handle 0x003A, DMI type 19, 31 bytes
Memory Array Mapped Address
        Starting Address: 0x00000000000
        Ending Address: 0x00FFFFFFFFF
        Range Size: 64 GB
        Physical Array Handle: 0x0035
        Partition Width: 2
[...]
Handle 0x003F, DMI type 20, 35 bytes
Memory Device Mapped Address
        Starting Address: 0x00000000000
        Ending Address: 0x007FFFFFFFF
        Range Size: 32 GB
        Physical Device Handle: 0x0036
        Memory Array Mapped Address Handle: 0x003A
        Partition Row Position: Unknown
        Interleave Position: 1
        Interleaved Data Depth: 2

Handle 0x0040, DMI type 20, 35 bytes
Memory Device Mapped Address
        Starting Address: 0x00800000000
        Ending Address: 0x00FFFFFFFFF
        Range Size: 32 GB
        Physical Device Handle: 0x0038
        Memory Array Mapped Address Handle: 0x003A
        Partition Row Position: Unknown
        Interleave Position: 2
        Interleaved Data Depth: 2
[...]

Memory is allocated by the OS

root@debian:~# free -h
              total        used        free      shared  buff/cache   available
Mem:           62Gi       156Mi        62Gi        24Mi       486Mi        61Gi

memtester verifies this is not a mistake, securing 61Gi of memory

root@debian:~# memtester 61Gi
memtester version 4.3.0 (64-bit)
Copyright (C) 2001-2012 Charles Cazabon.
Licensed under the GNU General Public License version 2 (only).

pagesize is 4096
pagesizemask is 0xfffffffffffff000
want 62464MB (65498251264 bytes)
got  62464MB (65498251264 bytes), trying mlock ...locked.
Loop 1:
  Stuck Address       : ok         
  Random Value        : ok
  Compare XOR         : ok
  Compare SUB         : ok
  Compare MUL         : ok
  Compare DIV         : ok
  Compare OR          : ok
  Compare AND         : ok
  Sequential Increment: ok
  Solid Bits          : ok         
  Block Sequential    : ok         
  Checkerboard        : ok         
  Bit Spread          : setting 109^C
(Process killed because this would take many hours to fully complete)

[1]: https://www.intel.com/content/www/us/en/products/docs/processors/core/8th-gen-core-family-datasheet-vol-1.html 8th and 9th Generation Intel® Core™ Processor Families and Intel® Xeon® E Processor Families Datasheet, Volume 1 of 2; Revision 008

Disclaimer: I work for the company that produces one of the computers you have referenced in your question.