You won't regain penile function after you go off HRT, afaik - and the way to retain function (particularly erections) is to ensure you have sustained, full erections every day. You have to replace the erections that testosterone causes your body to have naturally when you would be asleep. Without testosterone, you lose those involuntary night-time erections and thus lose capacity to hold as much blood and thus to be as erect, so the way to reduce loss of function is to manually give yourself those erections.
But yes, SRS is amazing and I highly recommend it - once I transitioned and lived as a woman it was very bad for my mental health to use my genitals like they were male, I actually wanted atrophy as much as possible and learned to wear underwear and use a vibrator to treat it like a clit. That worked much better for me. But SRS was much, much better for my sexual health.
You'll have to pay attention and notice what causes you to dissociate or lose connection with your body, dysphoria can be tricky to notice or catch (or at least it has been for me, esp. because I lived so long in denial, I learned to dismiss, ignore, and rationalize it away).
If you are gatekept in your country's medical system, you might also consider making a goal of earning and saving money so you can get SRS in Thailand, which is the go-to option for most people in the world who don't have access through their country's healthcare system. That might be easier and faster to make happen than waiting over a decade for potentially worse outcomes (and at this rate who knows whether that healthcare will still be offered that far in the future).
EDIT: oh, and your headline says losing fertility, but "fertility" is particularly about the ability to impregnate and your sperm's viability, which after a year on HRT has probably been already significantly reduced. Rather than fertility, maybe you meant penile atrophy and erectile dysfunction? Personally, I feel like penile atrophy gave me better sexual function, because it made my penis more like a clit. It's only if you think of the penis as serving a role as erect and penetrating (in a traditionally "male" kind of sexual role) that we think of atrophy as a "dysfunction" - and I just reject that, I think a female penis doesn't need to be penetrating, and functions well just the way it is (if not better).