Upvote for Kdenlive - it’s fairly basic but quite good at what it does do.

Give Kdenlive a try

DaVinci Resolve has a native Linux version, with the caveat that it can’t import mp4 files (have to convert them to another format beforehand with a tool like ffmpeg.) You also may have to do some tinkering based on your hardware - Arch Wiki has a good compatibility table, though the Debian packages will probably not match what Arch Wiki has listed, and you’ll need to use the installer from the Resolve website since I don’t think Debian has it in their repos.

If you’re looking for something free & open source, Kdenlive is also a great option, though it doesn’t have nearly as much functionality as its more professional-grade counterparts.

for me open-shot is great, and pitivi.

My 2¢: kdenlive works (worked; been a few years) shockingly well for being free without a commerical version. It’s not polished or fancy like commercial solutions, and it has had stability issues, but it really does work. Someone better than me could get professional results out of it.