I had FUT 13 years ago was on Androgel and it was fine, the Hair docs love finesteride , they will suggest topical if you dont like pills, I think it all gets into bloodstream, maybe less with topical depending on concentration. For sure my hair is better than if I didnt have the transplant, the transplanted hair does not fall out but the rest between or next to it continues to do so , TRT will likely help that especially creams/gels or high doses.
I could do with a second HT but havnt got round to it. I have never made the finasteride leap, dont like the sound of the stuff. Everyone to their own and we all respond differently.
The main thing with a HT is research it to death to find the best you can, and a honest one who will tell you the reality. The best ones dont tend to appear on Youtube which has some real crap on it.