Act 3 wraps it up. Shorter? Not sure. I always mix in side quests with the main quests so it blurs together.

aight thanks, i was expecting it to be shorter because 4 gaming sites said it just had 2 acts, thought they didnt want to make fals hope but obviously they are just plain stupid

Acts made sense in Witcher and Witcher 2. In Witcher 3 you had almost all map except Skellige open right after first visit to Vizima and could take on any quest at any time. Same with CP2077.
However if I remember right Act 3 starts with the "Nocturne Op55N1" mission and if it starts after you meet you know who in restaurant then try not to blink too much otherwise you might miss the whole Act. On a serious note though in Witcher 3 you had quite a lot of time after point of no return (Isle of Mists and 4 missions after that) in CP2077 you have one big mission and epilogue type mission/cinematic with credits roll. This is probably why people counted only 2 acts b/c the 3rd one simply does not register...

Act 3 is very short if you have done all possible side quests in Act 2 before pushing on to Act 3.