The 25/4 Scopar SC can indeed be adapted to a Z camera. I have the rangefinder (RF) version thus use a Nik(RF)-Z adapter, but M39-Z adapters are easily available as well.
The lens focuses to infinity on my Z cameras and is pleasantly sharp in a neat, small package. I mainly use it on my Z50 as the combination is adorably compact -- and capable.
Older Pentax Takumars in M42 mount also are easily deployed on the Z system, using M42-Z adapters. I do have the 35/3.5 you alluded to and it is a fine performer indeed.