DaVinci resolve is on a completely different level to shotcut or kdenlive. None of them are totally intuitive, but the required learning on something like Shotcut essentially boils down to understanding that pretty much everything is a video filter, or basic track operation hotkeys (e.g S to split video segment at selected frame, X to delete selected segment).
For your use cases I'd suggest taking another look at either of those and ignoring "advanced" settings wherever possible, it's really not that bad and you're unlikely to find anything on either Linux or windows that is both lightweight & does all that