Best set up for having to use own computer for work, while working from home

I totally agree with what @John Galt has said. However, if you are bent on using your own personal computer for work, I can think of two possibilities.

First, if you can gain remote access to your computer at work, you could use Microsoft Remote Desktop for Mac and just work directly on the computer at work with no need to "contaminate" your personal computer. MS Remote Desktop is free and available in the Mac App Store which is what you would use to work on the work machine. I have used such an approach in the past and works fairly well depending on the type of work. You will however need a reliable high speed internet connection between the two computers.

Second, if the first simple solution is not possible, you could create a second macOS installation either by creating a second partition on your Mac's internal drive or buy an external drive and install macOS on it and use these installations specifically only for work. Although it will keep your work and personal digital life separate, you will still have the pitfalls as mentioned by @John Galt.

I suspect you aren't going to like my reply, but my personal, adamant, insist-upon hard line nonnegotiable stance is that you should never, ever, under any imaginable circumstance under the sun, use a personal computer for employment-related purposes.

Ever.

Buy a different Mac, use a different Apple ID, never commingle the two. All you need to do is a simple thought experiment. You could be fired, your boss or your coworkers could be doing something illegal and implicate you in a desperate plea deal (it's happened) and what you thought was your own personal computer and everything you own or ever did with them become seized as evidence ensnaring you in litigation likely to last for years.

Coming from your own experience(s) what would be the most effective way to manage this going forward?

Don't do it.

Buy a cheap disposable Windows PC, even more so since you are contemplating using Microsoft products that don't work well on Macs anyway.