And the best way so far seems to be:
When character (that have Extra attack, duh) use action for Attack, all actions that should be useable again,
So essentially what Solasta does. What would be a bit more troublesome is that BG3 uses hotbar rather then authored UI - as such you don't have guarante what skills players will have visible in all time and therefore communicating they can still make additional attack might not work equally well for all players. Something could be worked out - like weapon icons having visual distinction between having attack being available or completely spent.
I suspect it might contribute to the reasons why Larian gives extra full action for now - it's a clearer indication of gained additional attack opportunity.
The question is tho, how about Special Weapon attacks? O_o
I mean, if i remember it corectly for example ... Piercing Strike causes our targets to get additional damage ... Pomel Strike reduces their AC ... Backbreaker knocks our enemy prone ... Rush Attack is free movement ... etc.
I don't think they are going to by any less balanced then they already are - the biggest balancing act for now is that one can use them only once per short rest so assuming it won't change with higher levels they should become even more of a side dish to the main attack.
