I stopped using the word "alternative" as it implies it maybe be less good. I just say "open source" now.
In reality, open source software almost always is a better product as it's designed by people wanting it, not by a bunch of managers wanting more money directing a bunch of developers who just want their salary.
Also: a lot of the mainstream software has Linux clients, if you look for them
I've been on Linux desktop and server for over 20 years now, reaching 25. Never looked back, never will