To what degree is prostate shrinkage an element?

I have basically zero scientific/medical knowledge, so this is partly just a question for the more knowledgeable members. Two of my most significant side effects have been watery ejaculate and testicular atrophy when going to the toilet. In the latter case, I can literally feel my pelvic organs kind of retracting, feeling small.

I am wondering to what degree these symptoms are due to finasteride shrinking my prostate. The prostate produces much of what actually contributes to ejaculate – I don’t know if it specifically has an influence on its wateriness, but I think this is an element worth considering. And that fact that my testicles sometimes shrink just gives me this strange feeling like there’s something already shrivelled up inside my body, which allows my testicles themselves to shrivel up from time to time. It’s hard to explain, but I do worry that finasteride shrunk my prostate and that a significant amount of my current symptoms come from this – I believe I’ve also read somewhere that your prostate produces a large amount of DHT.

Is there any medication that can increase the size of the prostate, or any consensus on this board as to what connection there is between PFS and the prostate in general? Would appreciate any information on this matter.