Suggest that you make sure your prefs are fully and properly trashed by downloading the free app “Preference Manager”.
Also suggest you run DISKWARRIOR. If you don’t have it, you can buy and download for about $70ish. By the way, you should run D/W more than once on each drive, because it sometimes misses something.
If you do those things, then, hopefully, you will have eliminated a lot of potential problems.
When I hit a phase where I am getting a lot of crashing, I usually reinstall the System and FCP, which really isn’t as awful or time consuming as it sounds.
In any case, that’s what I would do personally. I am sure other readers will have ideas which apply more closely to your particular situation.
best
Harry “The Crasher”