Finally ready to switch my final windows device over to linux, but I’m running into a problem. NTFS drives aren’t a good idea under Linux, but my 4 NTFS drives are this full. I own zero extra hard drives, and do not want to spend $300 on another one. 
How can I bring these files into Bazzite WITHOUT just wiping everything and re-downloading 10+ terabytes of movies, shows, music, games, and other data I refuse to delete?
Imo it’s best to leave D and E as NTFS. Maybe down the line you’ll end up with some swap space (maybe after you get that SSD for Windows), but for now it’ll work. I’d focus on getting the C drive empty as you can using the spare space in your other drives, then use it for Linux with a 200GB partition at the end of the drive for Windows.
I can’t advise re: games.