Disclaimer: I’m not working as a pentester, just an enthusiastic HTB player
I did it the hard way, installed Parrot on a dedicated machine and started solving the available easy boxes, figuring out what I need to use on the way. I don’t really like metasploit to be honest because it’s “magic”. I prefer to use / write scripts I understand so I can learn. Windows definitely helps when you’re hacking windows boxes. I made a conscious decision to work only from linux until it becomes literally impossible, and a lot of times this has caused me extra problems I needed to solve.