Mint should be pretty easy to get used to, solid choice IMO, as for the programs
Word, Excel, ect(I’m fine with alternatives)
If you’re fine with libreoffice, no problems
Spotify
Don’t know.
Gimp (would have been a make or break, so I’m glad it’s supported)
No problems
Brave browser (browser is a browser)
Not sure if there’s a flatpak, U might need to add a PPA, but it’s just a one time copy/paste a few commands.
Steam
Works fine, but some games might not run or require some tinkering, check games u play on protondb.com
Discord
It’s a bit annoying because they require u to have the latest version all the time, it won’t auto update, and the package might take a while to update, so u either download and update manually every time (it will be a different install than the flatpak package) or use the web version, peraonally i just run a script to download and extract the tar.gz version when there’s an update.