I’m in IT too. My experience is that if you use Linux at home and Windows at work you just end up skilled at both. At one point I was even using a Macbook at work (wouldn’t have even been a consideration if WSL was just a little better), using a Windows jump server or a VM for my Windows-y ops, and I became skilled at all 3 OS’s.
All of that is to say that your skill won’t decrease if Windows is still being used, especially if you’re using it in a professional context.
You got a lot of distro recommendations from across the spectrum and it’s honestly hats to go wrong with any of them. It’s mostly a matter of preference. As such I’ll give you two pieces of advice:
Good luck! IMO getting into Linux for the first time is a fun journey. Enjoy it!