Hey all, I'm trying to replace a faulty shower cartridge. The shower components have no brand names anywhere, and google searching them has revealed no matches.

SitRep: https://imgur.com/a/ROVB3nh

To replace the cartridge, I need to remove the shower handle from the wall. There are two steps, a hole on the bottom of the handle SHOULD (but conspicuously does not) have a screw or Allen keyhole in it to remove the handle. Second, a cosmetic metal plate covers the screw threading on the pipe.

As you can see from the pictures, the cosmetic threading cover can be twisted until it almost entirely off of the pipe. But the problem is there is no screw or Allen keyhole in the base of the handle (also in photos).

Despite the hole where a screw should be, the handle is extremely well-fastened onto what I'm guessing is the internal twist/control rod. There was some kind of caulking filling up the hole (in place of a screw) which I've carefully bored out.

Any tips on how to remove the handle without damaging the control rod?

Thanks!

https://imgur.com/a/ROVB3nh

I’m trying to tear down the shower tile, but I can’t seem to figure out how to remove the shower handle. There are no apparent screws to unscrew. I’ve tried twisting the metal piece behind the knob for ~10 mins. I have no idea what to do. Please help! See video