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.
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.
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.
Yeah, Kdenlive. You can do a job with it, but like most software, you need to put some time in to learn the ropes. YouTube is great for tutorials. I've used it to cut up screen recordings (recorded with OBS) and turn them in explainers, dropping in stills as title backdrops, even doing shrunken down videos that looked like they were playing on a laptop.
I was pretty happy with that anyway.
You can record voice overs directly into Kdenlive, but the audio editing is next to non-existent, so you're probably better off editing it in Audacity or Ardour and cleaning it up there, and then dropping it into Kdenlive.
For context, I'm a developer, not a graphic designer or anything, so me achieving any video editing results is a thumbs up :)
easy. open up terminal. launch vim. start writing a MLT-compatible XML file with your edit choices. exit vim (you know how). run the melt export timeline command. video done.