Hello all!
just started QFG5 (imported my Paladin) and I am wondering if there is a time-limit, regarding certain actions that if you miss will lead to dead-ends and stuff like that.
Thank you.

No dead ends. Some sidequests and Rites can time out, but all that will happen is that you'll lose the Rite or miss the sidequest. One Rite in particular can be lost, but you'll still have to do it - it's the only way to get a key item you'll need for the next Rite, that can't be lost.