Repetitive how? I never got that vibe from S5.
Every season is Tommy needing to find someone to defeat and go up and up. Reason why is because Tommy is suicidal ever since WW1 and wants to die but is too big of a coward to do it himself, so he forces himself to always challenge people in hopes one day someone stops him.
That premise worked for 2 seasons because by that point he established himself as a main bookie and overall business man in England while defeating everyone in his way - mainly Campbell. By that point in the story Tommy virtually has no enemies... except Lucca
Lucca is perfect ending to Tommy, he isn't someone Tommy must defeat in order to advance up, he is someone Tommy needs to defeat to keep his family safe which is a step forward from his suicidal tendencies. Lucca pushes Tommy to the extreme and Alfie exposes Tommy's hypocrisy in his way of life. Tommy deals with Lucca and keeps his family safe while dealing with Alfie too.
A good character arc
Only for Tommy to take a fight with Mosley which makes no sense - Mosley is a facist and he views Tommy - a gipsy - as not even human - as Nazi's did to Gypsies. Yet Mosley in PB is perfectly fine with that. And you can't use Tommy's influence and money as a leverage bcs Mosley IRL had backing of several prominent English Nobility and he had funds, hell Mosley was active up until late 1930's and even early 1940's, he died of old age if i am not mistaken in 60's.
It is a forced plot line which shouldn't have existed. Tommy's arc perfectly ended with Lucca. Mosley stuff is repetitive of stuff we've seen before. And Michael, jesus christ. Not even gonna go into that atrocity of a character.
So i chose to stop watching the series and only read summaries post mosley appearance. For me PB ended with Lucca which closed all plot lines properly