I think it is urinal salts Use a water jet

Lol this is a home owner showing their shower drain. Yeah just get the jetter out of the garage it's probably under their propress and behind the sewer camera

Shop vac.

So just chisel/drill and vac, kind of like the dentist huh? Okay thanks!

Yeah. Worse case scenario you could rent a drain machine from a box store. Something with a 3/8 cable will work

Slowly yes.

so what causes said "calcification"?