I’ve owned a bunch of boats, & still have 8 different watercraft on the dock. I’ve seen tons of underpowered setups.
In my opinion, you are way underpowered for what you want to do. I used to have an 18’ Lund Tyee, a deep V fishing boat, with 115 Merc. That was decent power for tubing with the kids, our amateur water skiing & fishing. We also had a very lightweight 16’ fibreglass shallow V with a Mariner 90, that was also very adequate.
Glass Cuddy cabins are heavy boats, you can certainly plow around the lake, but where the real power is required is getting out of the hole & up onto plane. Remember, you need some required gear in the boat, fuel, at least one spotter,(and probably a few kids/parents watching). Trying to also get a skier out of the water, or a tube on plane, (we often double tubed), isn’t going to happen. Going to a low pitch prop with only 50 hp might get an empty boat on plane, (if you move people forward into the cuddy),but now you have to be very careful not to overev the engine.
Dealers are part of the problem. They put together underpowered packages to show a much lower price. The new owner is disappointed, sells the boat to another unsuspecting owner.
what is the Max HP listed on the certification tag? Try to stay at 3/4 of that, if not more. There was a reason it used to have 100 ponies