You need something that effects collagen synthesis. 19-Nor derivatives might help you there. HGH ....to a lesser extent, BPC 157 / TB500. Honestly if you have the money, those cultured stem cell injections you can get in Puerto Rico might be worth it.

The world has changed a lot brother.
If your injury is ligament based, I'd say stay away from the test. It's great for maintaining strength etc but it's not going to have a positive effect on ligaments, maybe the opposite.
HGH is great for healing, it's expensive but worth it, still not my first choice.
My healing cycle looks something like this:
TB500 10mg 1x a week for 6 weeks, then drop to 2mg or 5mg once a month after that.
BPC 2-3x a day, 1 site location, 1 sub q, 1 oral.
mk677 25mg 1x a day
Prebiotics and probiotics should be taken throughout, especially before your surgery. You can start all of this before your surgery. I'll break down what all this shit is now.

TB500, this is a healing protein derive from the thymus, yadda yadda technical bullshit, what it does is increases healing of all tissue in the body, primarily skeletal muscle tissue and ligaments but it's also one of the few that can protect the heart and one of the only things that can help repair the heart after a heart attack. It will also increase your cardio endurance

BPC157 is literally body protection compound #157, it was derived from gastric acid and designed with the purpose of healing. This, along with TB are going to be your big hitters with healing. My dosing protocol isn't based on any studies, it's personal. One because I hate pinning so often and two, because I do believe saturating from every point helps.
BPC reportedly also has a site location effect for healing and is bioavailable since it comes from gastric acid, it's just going back home. When you get fucked like this, it's not just your knee that's messed up, it's your whole body, and your digestive system takes a hit. Your gut is probably the most important and often neglected system in your body in terms of healing, so keeping your gut healthy and pumping it with healing property will help your body heal better and faster. Sub q in to the belly fat is just easier than pinning the knee constantly and even though it has site location positive effects, it will still spread throughout your body.

MK677 this is a growth hormone secretagogue, AMAZING stuff, truly is. It'll be the equivalent of about 3.5iu of HGH per day, which is a good healing dose, maybe a little higher than that. Be careful with how you eat, do some reading on schedules of when to take it and what to eat before and after, just like HGH it has an effect on insulin and you don't want to blunt that with taking in carbohydrates too early. MK is probably one that people can take year round with short off cycles. It does everything HGH would but is MUCH easier to take and IMO, a cleaner baseline, plus it's making your body work instead of taking in a foreign substance which is always ideal.

Honorable mention, when you get back to it maybe consider GW to get your endurance back on track.

None of this will have an effect on your endocrine system, they're not steroids, I don't believe you want to use steroids at this point. Good luck with your healing brother.

-PRE POST EDIT-
I actually, didn't read your title fully. I see you're already on TRT, that changes things a bit. I would maybe add in a therapeutic dose of deca or EQ to aid in joint lubrication and ligament strengthening but not enough to have any other real effects.

If your friends had similar issues and success why not just do what they did.

Bpc 157 and TB500

Hgh is debatable, there’s med lit showing no improvement on tendon/ligament healing times, however a lot of anecdotal reports of guys who used it to accelerate healing. IME I sleep deeper on hgh, and I know sleep assists in injury repair. So even if it’s just an expensive sleep aid, it may be worth a look. It’s pricey but at your age probably something to at least consider with a coach/doctor and see if it might be helpful.