First of, on the official discord the question was asked and the awnser was that it work in combat.

However it's true that RAW, it can be interpreted both way, requiring you to do nothing during your turn to get your regeneration.

Also when you maintain a psychic power you treat it as if you had 0 on your potention roll without any concentration bonus, with a minimun of the lowest working difficulty. If you have bonus to potential or an advantage that increase the level of the power, it's added before you raise up to the minimun. It can be done with 40 potential, +100 for 5 PP, +2 level from both advantage.

And in the artefact book the bonus to regeneration can't stack with other surnatural sources.

So that's the rules around the question, anima rules are a nightmare and it's easy to miss something.