Finasteride or dutasteride. They control BPH perfectly, while also treating male pattern baldness. Combine with daily tadalafil to offset any chance of the dubious sexual side effects, while also reducing gynecomastia (it's also an aromatase inhibitor!). Make sure to have regular 5ari-aware PSA screenings to make sure high grade cancers are caught and you are golden.
fin/dut + tad are my favorite medications to keep men fresh for many more years than intended by nature.
Have your children before you start though, as dut will probably make you sterile eventually.
I've personally had very little luck with official channels there. Most won't prescribe anything for hair loss, several dermatologists said to just get used to it, one would prescribe fin pills, i.e. systemic - which did eventually give me pain in the breast tissues (so I ceased using it), but not topical, citing that it's too new on the market. I was unable to find anyone who would or even could look at serum DHT. I eventually settled on just paying one of these apparently legal telemedicine vendors 20 bucks per topical fin prescription.
You already decided to take one hormonal disruptor, so why not go all the way? Find a private andrologist that prescribes you fin/dut + an aromatase inhibitor. Daily tadalafil also acts as aromatase inhibitor by the way. Should be enough to offset the estrogen increase from finasteride. It's worth a try.
I personally don't really believe in topical min/fin/dut: You are probably just getting the same effects and side effects you'd get from a lower oral dose.
The studies on topical finasteride support this. You just believe it's not in your blood and thus there is no nocebo effect to give you ED but it very much is.