Fwiw, this has been helpful for a couple decades now:

https://symless.com/synergy/features

Given that even a corp Mac can now (policy permitting) allow a personal AppleID along with the corporate login, it's easy enough to do the same with just native OS controls even with 2 logins. Something magical about opening an iPad next to a MacBook and pushing the cursor across ... or, alternatively, wirelessly (or USB-C) making the iPad an extended screen.

But Synergy remains great.

If free is your bag instead of supporting the nominal cost:

https://github.com/deskflow/deskflow

They explain this here:

https://symless.com/synergy/blog/how-to-use-synergy-for-free