Booting into personal mode wouldn't protect the user from having to return the laptop without notice in the event of layoff/termination, without any opportunity to recover or erase personal info. It also doesn't nullify the right of the corporate IT, HR, legal, etc. to inspect any data on the machine, personal or not, at any time. It's utterly not worth it even if it were offered.

All around terrible idea to mix personal and work. Your work computer is always subject to investigation and potential seizure by authorities, not to mention many corporations leverage MitM proxies or other local logging software at the machine rather than user level.

I assume that anything on a work machine is potentially compromised. Having a strict barrier between work machine and personal machines eliminates any embarrassing cross-contamination between them.

If you want to eliminate having duplicate hardware, this is perhaps the only use case I can think of for thin clients/cloud desktops that isn't a step backwards.

I’ve done exactly this before a few times.

Had a laptop that dual booted into a different installation of Ubuntu on the same laptop, one for personal and one for work (Ubuntu LTS)

I have a separate user profile on my current computer for work stuff. I also use a separate web browser and email client for work but now I share the same OS and the files are on the same SSD.

It’s trivial to switch users on a desktop OS nowadays.

The biggest issue I run into is that my work environment needs me to set my SSH config to use my normal username rather than the username the work profile has.

It should work if you have an OS with a strong isolation like Qubes OS.