VOLVO S60 D5, 2006, starter issues

[Kristers18]

Recently i had problem with starting the car, i had really annoying slow crank. Now in my country it’s pretty cold and one morning while making cold start starter just died. I thought it was a battery but no, battery STH is 70%.STC also is good. I checked relay but it is good. Starter is engaging but not spinning. I cleaned it, lubricated it and putted everything back together. After like 2 weeks it is dead again, i push- started my car and starter is working again. It was pretty seized when i tooked it apart but now i don’t know what to do, maybe solenoid is bad? What to check next? Btw internal parts was looking fine, just gears was dry and bushings and bearing. Sorry for bad English….+ hitted deer today so have more problems to deal with , those cheap chinese starters scare me with they’re poor quality but original starter costs big big money atleast in my point of view.