(had this same problem with Fallout 1 took like 2 years between buying it for it to 'click' and even then I only realized at the Cathedral I could reload without going into my inventory)
I haven't played enough of Tactics to even remember exactly how the system works. But most cRPGs even those in real time with pause will still have effective "turns." In Tactics, I think it's similar to 1 and 2 but it's also got regeneration in real time mode.
The base value of your action points will be 5 + [Agility / 2] I think for all the classic games.
3 Agility; 5 + 3/2 = 6.5 which is 6 AP
5 Agility; 5 + 5/2 = 7.5 which is 7 AP
6 Agility; 5 + 6/2 = 8 AP
10 Agility; 5 + 10/2 = 10 AP
As for AP regeneration I think your Agility stat also modifies how quickly it regenerates or it might be that to get your maximum AP again takes the same time regardless of your maximum so if you're regenerating 10 AP for one character and 5 AP for the other, the 10 AP character would have 5 AP before the 5 AP max character would and therefore appear to and effectively have action points generated faster.
If you dislike the real time, there's a turn based option in Tactics though I'm sure it'll make the game take a good bit longer. For a few reasons, real time with/without pause games are more likely to have fodder enemies to pad out fights and areas (not always true but seen it enough times) and the other is that the game was designed that way so the alternative method is likely a bit ignored in how it turns out in the long run. It's also a very combat-centric game so staying in turn based only mode will naturally make it take longer. If you can toggle between them easily, maybe start on turn based and swap to real time whenever fights seem like they'll be easy enough that you don't need to optimize your AP usage?