I do some video editing, have tried kdenlive, davinci resolve, openshot and shotcut. I currently use Kdenlive. All of them excel at sth and failed at sth. Here's what I've found:
Kdenlive (Free): relatively easy to learn and UI is clean and intuitive. Have audio graphics in the timeline. Slow rendering.
Davinci Resolve (Free): A bit of a learning curve, but not too steep. Fast rendering. Have audio graphics in the timeline. Does not support .mp4 (on Linux), you'll have to convert to .mov and then from .mov to .mp4 (if your target file is .mp4).
Openshot (Free): Very easy to learn. "Decent" rendering. Doesn't have audio graphics in the timeline.
Shotcut(Free): Not too difficult to learn, but it does require some time to get use to, mostly because of the UI being a bit "unusual". Have audio graphics in the timeline, quite small, tho. Rendering is "Ok".
Depending on the kind of project you do and your workflow, some of the editors I just mentioned might or might not have something you want/need, you'll have to try one at a time and chose the one that best meet your needs. Kdenlive doesn't have the ability to record the screen, nor does OpenShot, not sure about the other 2. There's also flawblade and olive, haven't tried those two.
Note: Davinci Resolve is the free version, and Davinci Resolve Studio the paid one, which I believe does support .mp4 files in Linux.