Thats a good wake to learn some stuff on. Common misconception that you need the biggest wake. Big wakes are fun, but smaller or medium size wakes are fun too. If you are just learning this will be better for you also
If my sorry behind can do back rolls behind an old 93 moomba 17 foot ski boat with no ballast and no tower or flight pipe you can too, its all about using the energy. You can make great progress on small wakes.
Yes, that wake is small. Can you slow down a little? 22mph may be a little fast. I'd try 19-21 and see if that helps. Shorten the rope if you have to when you slow down. It will make learning easier.
I bet you could get it bigger by adjusting the trim since that boat is an I/O. A long time ago I used to go out with a guy on a 19' Mariah and it had a bigger wake than that with the trim adjusted. That Cobalt is a deeper hull boat so I would expect more.
But as others have said that wake isn't a limiting factor and at least you have a tower.
It's very hard to get a decent wake on a runabout. these boats are designed to get OUT of the water. Wake board boats are designed to sink in and displace a lot of water.
try a shorter rope and a slower speed- like 19. and get a lot of people or weight in the boat.
Ditto Times New Roman. Same size as my wake, we learned plenty of inverts of it. You're less likely to injure yourself. Slow it down a fraction if you need to.
On that wake you should be able to accomplish a T & H 3, back roll, tantrum, scarecrow, solid grabs. If you get good enough with T3's you could probably land a T/F 5 on that wake. Having the rope higher up with totally be to your advantage.