currently it will be nearly impossible to fight the cloud anymore since its dead content imo. blame the level cap raise for that.

outside of that gilgamesh shouldnt be a problem to fight. just do hilidquest. he is part of it and is also part of duty roulette trials which alot of people still run daily.

you can still start and do some of the tower questline. but getting into the 3 towers will be nearly impossible currently except if you are willing to wait countless hours for it. maybe they will adress that with patch 3.1 but anytime before that probaly not. i would say wait for 3.1 and check then again.