The other day the turn on this shower was very stuck. I managed to move it, but now the max hot is not as hot as it used to be (and not hot enough to shower) .

As I took it apart, I discovered the back of handle was broken. I think I was still able to move it to the max position, but it's possible it wasn't moving the actual cartridge. Other faucets are OK so I know it's not the water heater. Do you think just replacing the handle might fix the problem?

I'll first try to replace the handle... Though it might have broken bc the cartridge was sticky. Can someone help identify the right cartridge in case I need to? And am I on the right diagnosis path here? Also I've never replaced this but I'm decently handy... Any tips would be appreciated!

From what I can tell I don't have shutoff at the valve so I'd need to shut off the whole house water to replace (we don't have individual bathroom shutoffs). I'd like to avoid a cartridge replacement if it can bc if I fail at it, I'm out of luck until a professional can come repair my mess.

The house was built in 1993 in Texas. I'm not positive if this bathroom has been redone... It's definitely gotten a face-lift but the tile seems original.

Lastly, is there a replacement handle without valve change that is more lever action? This one turns right/left and the straight out to increase water flow. This shape is hard for my kid to use (also might be bc the cartridge is a little hard to move for a youngster)

Thanks