ACES (AP0) is an archive format for when you want to be absolutely sure you’re not clipping any colours. As a working space it’s terrible and AP1 should be preferred, either as ACEScg or ACEScc
AP1 is almost the same as rec.2020? I'm not sure what you mean by 'working space' but if preserving all colors was a primary or even secondary goal I definitely wouldn't cut myself down that far.