We've been on Regal Princess 3 times and really like that ship. The British Isles cruise was in Summer of 2023. It is very much more laid back than something like Carnival or
RCCL. Entertainment-wise we loved it, but we are not really big production show people. Where I thought Princess excelled was in having a ton of smaller entertainment things going on like game shows, tons of live music (the crew band on that trip was a highlight), smaller acts, trivia, etc. We were never bored.
Also, you may read mixed reviews about the Princess medallion. Yes, it doesn't work great on some ships, however, at least for us, it worked great on the Regal.