w32tm does not exist as an installed service

I've been having trouble with the time on my Windows 10 PC. I've googled several different solutions. The first one I tried said to do a

w32tm /unregister
w32tm /register

When I did the second command, it said something like "Service has been marked for deletion".

Now if I do anything involving w32tm or W32Time, I get some variant of "The specified service does not exist as an installed service".

How do I re-install the time service without re-installing Windows?

Yes, this service is not found in "Turn Windows features on & off" or any other place. But the command you gave:

w32tm /register

Is the actual way to install it (using a command prompt which was Run as Administrator). Sometimes you need a reboot to put things in order, but I actually just waited a while without rebooting. Here is my sequence of commands showing that it works:

(base) C:\WINDOWS\system32>w32tm /config /update
The following error occurred: The specified service does not exist as an installed service. (0x80070424)

(base) C:\WINDOWS\system32>w32tm /register
W32Time successfully registered.

(base) C:\WINDOWS\system32>w32tm /query /source
The following error occurred: The service has not been started. (0x80070426)

(base) C:\WINDOWS\system32>net start w32time
The Windows Time service is starting.
The Windows Time service was started successfully.

(base) C:\WINDOWS\system32>w32tm /query /source
Local CMOS Clock