I'm running an 8-player 5e group in a completely custom realm. Everyone is pretty close friends and most of us have played together before (with me as DM 90% of the time), but this is the first time we've gone over 5 players and the three new ones are first-timers. In preparation for a large group we've put some rules in place to keep combat moving smoothly, but in the RP parts things get bogged down by everyone wanting to explore this or check that or persuade this person or decide who should be the first to step into the tavern because "reasons".

This is all well and good for 7/8 players, but one of the vets is particularly annoyed by people "wasting time" this way. I understand his frustration because it really does slow sessions down and limit us to about 1 encounter per session (and he likes rolling dice slightly more than talking), but everyone else is having a grand old time smelling the roses and getting into trouble with the locals.

I'm not going to kick this guy out because his playstyle is slightly mismatched with the rest, but he's told me of his completely understandable frustration with the situation and I want to help. Is there some way to inject some more action for this guy without disrupting the fun for everyone else?

Things I've considered but have either dismissed or been unable to work out:

• Making him the secret villain (not sure how that would add interest on a daily basis)
• Having someone take out an assassination contract on him so he's occasionally assaulted or trapped (the party would likely wipe the floor with whatever ninjas are sent after him)
• Have him get randomly pulled into another realm and assailed by daemons (would interrupt everything else and ultimately serve no purpose)

He did suggest (in private) early on that he wanted the story to include him getting turned into a werefolf, which would have made some more action as the party had to deal with his transformations and the progression of the disease, but that ultimately got struck down when one of the other players rolled a Paladin of the Silver Flame by coincidence.

What would be an easy way to give this guy some more interesting action without forcing the rest of the party to change their play style? Preferably something that can be worked into a story and isn't just an arbitrary "You get assaulted by giant killer bees constantly for no reason" situation.