bath cartridge replacement help

So the bathtub faucet leak kept getting worse. I have learned quite a bit like how to even ask this question... I cant figure out how to replace the handle, no cartridge ive found fits. Anybody recognize this setup? Hard to see more, whoever worked on it last dumped concrete like stuff around...

Looking for a vendor ID.

TL;DR - Stem for tub and shower faucet is plastic with D broach, has threads on inside of broach which the handle adapter and handle itself screw into, part numbers on handle and adapter resulted in mixed bag of Valley brand search results, unsure of part to buy, links for parts I’m considering...

I have an old bathroom faucet that will not turn off. Am trying to find a replacement for this cartridge. The broach has 12 splines and is a little under 0.34 inches in diameter. Thank-you for any ideas.

Ok, I am in need of a little help. I watched a few videos and read a couple of instruction guides on how to replace a Moen 1225 cartridge. The replacement went well, and with the initial test it works fine. The problem happens when i get everything back together. When the water is then turned on...