Share monitors and peripherals between Linux PC and 2020 Macbook Pro 13" [duplicate]
Are KVM switches even needed anymore for MacBook Pros?
As special as we'd like to believe MacBook Pro computers are, they're still computers with industry standard connectivity like USB, video, etc. What works for a PC laptop or desktop will work equally as well with a MacBook Air/Pro laptop and Mac desktop.
Do you need a KVM? No.
Just get a quality monitor with multiple inputs and a keyboard/mouse combo with multiple connections.
You've already mentioned Logitech Flow which allows you to use a single mouse/keyboard across two different computers simultaneously (i.e. cut/copy in Windows and paste in macOS).
Though convenient, it's not the exact product you would need - it's actually something simpler: multi-device connectivity. The same Logitech products like the MX Series keyboard and mouse have the ability to pair up to 3 different devices. A simple press of a button will switch connectivity from one computer to the next.
Is there some sort of magic Wi-Fi / Bluetooth / Airplay device that can perform the same function.
If there was, you'd still need to switch it. WiFi, Bluetooth and AirPlay aren't magic and give you features where none exist. They just replace wires as a matter of convenience. You don't suddenly get KVM capability because you can stream video without cables.
And...if you're looking at software, that means at least one computer must be booted at all times as it has to be the host. If you're going to spend the money on software, you might as well get a hardware solution that's platform agnostic and much more reliable (i.e. the next version of macOS breaks it and requires an upgrade)
Is there software that can perform the same functions?
I ran across FOSS solution for a software based KVM called Barrier. It works on macOS, Windows, FreeBSD, and Linux. Binaries are available for both macOS and Windows. It is also available via Homebew and available for FreeBSD as both a package and as a port per FreshPorts.
It’s actually really cool software that allows you to arrange your setup graphically so that you can “move” your mouse across the screen “barrier” and onto the next computer (i.e your Windows machine is to the left of your Mac). It also allows you to assign a keyboard shortcut to select a different computer to control.
It’s only limitation is that it doesn’t switch the monitor as a traditional KVM would. You still need to either have individual monitors for each computer (not a problem if using laptops) or a monitor with multiple inputs. There’s an excellent YouTube video showing how it works with a Windows machine and a Raspberry Pi.
Just get a quality monitor with multiple inputs and a keyboard/mouse combo with multiple connections.
Many high end monitors include a KVM function. Some people don't realize that their monitor includes this function. If your monitor has USB-C and USB-B, or more than one of those two, then it almost certainly has a KVM function.
There are software solutions but they will still require fast enough computers and networks to be useful. 1080p/60Hz video will take more than 3 Gbps to send over a video cable or network. Compression can help but this will add to the delay. 4K/30Hz will take twice that bandwidth. If you connect the two computers directly with a Thunderbolt cable for the network then it's likely a software KVM will work nicely.
If you are looking for suggestions on a hardware KVM I can say I've used StarTech at a place I did some contract work and they perform nicely. https://www.startech.com/Server-Management/KVM-Switches/
I'd say first check if the monitor you have now has a KVM function in it already, you may be surprised. If you are looking for a new monitor then see if you can find one with a built-in KVM that fits your needs and budget. Software KVMs can be cheap, or free since there's plenty of FOSS options. Then if all that fails (for whatever reason) open up a web browser, and your wallet, and shop for a hardware KVM. Remember that a big shortfall of software KVMs is, by my estimation, in the network so don't give up on them too quick if there's a cheap way to get a fast network connection between the computers. With two MacBook Pros on the same desk it might only take an $8 USB-C cable to get a 10 Gbps network between the two.