I'm on a mid 2017 iMac, and I did the QTA update. Almost every app crashed with Finder just lost if you will. I went to the app store, searched for Mojave and got the full installer, and it's better but still getting crashes randomly. It appears skylight is one issue so far. I've been exclusively Apple since 1999 and this is the very first issue I've had whatsoever. not even a minor breakdown. Oh, I had a button battery de on my G4 Silver two decades ago

. With my lack of troubles, comes a lack of knowledge though and I'm struggling for answers. Anyone have any advice, before I do a clean install? It ran "perfectly," on 10.14.5. Not a single crash.
It's an 18,3 iMac, Radeon Pro 580 GPU, 32Gb ram, i5, 3.8 GHz, 2Tb fusion. I know

lol. I'll wait another year and drop a 4Tb ssd in it or two in raid, if I can keep from taking a baseball bat to it first. I love it actually, and I don't beat things up, except for myself.
Any advice would be welcome. Thanks.