18.6 has a bunch of bugs!

Most of those using CapCut are happy with it and, as I've said elsewhere, it's probably a much better option for the non-professional editor who prefers ease of use over the many pro-level features that Resolve offers.

It's probably not a bad thing that CapCut is gaining a lot of popularity because it will reduce the number of folk for who Resolve is not truly the best option. If you're not editing or grading on a daily basis then Resolve's learning curve is probably going to get in your way and if your hardware is not up to scratch then the Resolve experience might be more than a little frustrating.

Horses for courses, as they say.

CapCut doesn't have as fancy audio processing in the free version, so when I sped up my audio, I had to sort of fudge the pitch down a bit. Also, the color correction doesn't have the histograms that DR has. But it works really well on my machine so far.

It has color oscilloscope option located in corner of preview window, when speeding up audio has a pitch correct box to tick next to the speed control, but you surely must have seen that so I assume doesn't work as expected. Being a purely monthly subscription model for the pro version is a negative

Just to be clear, I did try 19. Crashes out within seconds. Had to revert to 18.6.4.

Seems to be a massive incompatibility with your setup. 19 is already running OK'ish here. Some issues, but no showstopper like yours.