I’m a software engineer, and I’ve used Linux on my computer for work before when my company allowed Linux installs on their computers (most don’t in my experience). I don’t recommend it for you.
For me, my main productivity tools, even proprietary ones, run natively on Linux. I very very rarely have to do anything involving word processing. When I do open source or in-browser word processors are enough. Windows can also be a constant headache to use in a lot of software development settings. It’s a horrible development environment. I try to avoid working on Windows as much as I can.
When something breaks (and on Linux, something eventually will), I have more than a decade of technical experience in computing I can fall back on to fix the issue myself. My work computer has failed to boot before and all I had to diagnose and fix the issue was a black screen with a terminal prompt. Even my company’s outsourced IT company had very little experience with Linux and I was largely on my own to fix it when things went wrong.
For you I don’t think it would make sense for basically all the opposite reasons. I imagine you’ll be doing heavy word processing and editing a lot of documents that need to be formatted correctly. Browser based and open source word processing are probably not going to cut it. I’m not sure if there are any proprietary file formats you may come across in the legal field, but if there are do you want to have to ask people “could you send that in a different format? I can’t open that on Linux.”
If something goes wrong on your machine you may not have all the experience to resolve it quickly on your own which could impact your business. Windows can break too but there’s a lot more support out there and the barrier is much lower to fix most issues (I can’t remember the last time I had to bust out a terminal to fix something on windows)
For all its faults, windows is pretty well set up for your typical use case.
If there’s a compromise here, you could try having a computer running windows and another running Linux. Having a backup in case something goes wrong isn’t a bad idea anyway. Dual booting is also an option. I made it through college for a CS degree with a dual boot Windows+Ubuntu laptop.
Whatever you end up doing, be sure to have a really good plan in place for backing up everything you need, especially files. Your computer can fail you at any time, Windows or Linux.