Upvote for Kdenlive - it's fairly basic but quite good at what it does do.
Linux
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.
I'm a big fan of Kdenlive!
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.
Shotcut, Kdenlive has a really weird UI and Davinci's linux version doesn't support .mp4 files.
I've used shotcut quite a bit. It's pretty decent, my only gripe with it is that it's ability to handle captions is fairly terrible but if you have an alternate method for captioning then it's everything most people would need.
Kdenlive
Kdenlive is a pretty good video editor. If you want something more advanced, you can use DaVinci Resolve.
Kdenlive is pretty good, but I also really like Olive.
Blender!
It's got a learning curve to it, but the sheer amount of stuff you can do in Blender is actually kind of mind-blowing.
I don't think that's what OP is looking for, unless Blender added a really good video editor recently.
DaVinci Resolve is available for Linux..