This! Simply presume kdenlive will frequently crash. I found it very disconcerting at first, but I learned to treat kdenlive's frequent crashing as a mildly annoying glitch (peccadillo).
I use kdenlive for quite a bit. Crashing can be a problem when using the system repo version, but when using the flatpak it's very stable. If you haven't tried that, I would recommend it.