I think I got this fixed.

I changed my laptop display from 144hz to 60hz, and it didn't crash in the new raid this time (first time today of several).

Just also remembered, that I had similar issue before (outside ff14), as my laptop was 144 and my external display 60 (and can't go higher). Changing this now also made my external display picture or fps smoother.. probably, as the 2 are now better in sync.