I have started leaving without the round. A text the next morning is easier than the group goodbye.
being the first one to leave a party
The hard part is the door. Everyone says "already?" and you have to explain, in one sentence, why you are tired without sounding like you do not like them.
You do the round: coat, thank the host, say "we should do this more often", and leave at 21:40 while everyone is still deciding where to sit.