First off, I love Linux. It’s my daily driver and I wouldn’t want to use anything else.
But in my past career I was the CIO at a very large firm. Lawyers need Microsoft Office and Windows. If you hire a good assistant or paralegal with word processing experience, they are going to need Microsoft Word. LibreOffice is good, but it’s not a replacement in this scenario. Good word processors are like wizards and will save you hours. It’s not worth it to make them learn something else.
Then there’s drafting software, templating, practice-specific tools, etc. Anything geared for legal is going to run on Windows. What are you using for time entry? What about accounting?
Not to mention, you have some information security obligations under the model rules and you don’t want to mess with that. Although Linux has security advantages over Windows, you still have to take measures to secure it. Maybe that’s easy enough for you to do on your own laptop, but your practice will grow to at least a few staff and an associate. Somebody has to do IT because you’re sure as hell not going to waste billable hours on it.
I had to use Windows in that old gig and it really wasn’t bad. It’s stable, reliable, easy to support. Everyone you hire will have used it before. It’s an unpopular opinion around here, but it’s a quality operating system that’s affordable. I guarantee your cost of ownership will be lower on Windows in your particular situation.