So I have since done some reasearch into this (and I suggest you do the same, if it isn't obvious) and found that a) you can't run the Action! app in Game mode, instead it needs to be run in Screen Mode, and b) I have to set my game to Borderless Window and c) I have to add the game to the exclusion...

I have just installed (and re-installed) the trial verison of 4.38.2. Almost every game I have tried to run while recording is on, crashes to desktop, including Baldur's Gate 3, Witcher 3, and Elden Ring. RDR2 seems to be OK, but AC Odyssey keeps losing focus. WOW. How can an established program lik...