LinkedIn and Indeed mostly, though I do check my resume against the listing using stuff like jobscan.co to play the stupid match-the-keywords game to rank myself as high as possible. The response rate sucks but I do get responses, and I think shitty response rates for applications via job boards is kinda common in general. In my area (both geographically and career-wise I suppose) there are also plenty of recruiters looking for people to get in the door, which gets you past the AI gatekeeper. Though recruiter activity has slowed down in the past year and it’s not a time of plenty anymore they’re still around.
As with anything YMMV. So many variables, and surely some luck has played a part in my experience.
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.