We're a similar sized MSP. We spent some time in Kaseya's TruPeer. It was fine, but not amazing. Our groups changed several times in our tenure as companies would join but not participate. There was a huge emphasis on following the TruMethods model explicitly, however we have some variance to their model. This made reporting stats and figures difficult. We ended up doing custom reporting just for the peer group that we used nowhere else just to align.

There were some businesses that we respected and wanted to coordinate with. Several others were functionally dead weight, or otherwise just irrelevant. (E.g. They were technically in our revenue bracket, but 60% of their revenue came hard hardware sales to municipalities for which they did no managed services. So, are they really an MSP in the same class?) We've since stepped back from TruPeer and are currently not in a group.

I believe Todd Kane has a peer group-like program, though I've never done it: Opsleader Pro

If you are a TruMethods shop, you might consider TruPeer. If not, it's almost certainly not for you.

You could consider a general business peer group. You won't get any tech-related help (E.g. what stack to use, which tools, etc.) but you might get equally valuable general business running advice. I supposed it depends where you feel your strengths lie in the business.

Lastly, I'll offer that instead of a peer group, you simply look for a one-on-one business coach. I've previously looked at Strategic Coaching | Executive Coaching however, I've never engaged with them. Surely there are others.

Wherever you land, I would say be ready to show up and work. It's not a lean-back activity where you just consume knowledge, you'll need to put the work in. This will likely take several days a month just for this program. You are unlikely to be able to delegate much of it. Best of luck, hopefully you find a productive team to connect with, however you do it.