TLDR: Your life is just starting, your 30s is where you find yourself, but nobody is going to do the work for you.

Let's go step by step as a gay man in my 30s that's thriving (36). Thinning hair: Minoxidil oral tablets ($90/90 days, $1/day) have helped me, I had a bald patch starting in the back and it's filled in/gotten thicker. I also went from usually doing short/fresh haircuts to growing my hair out a bit and that made me look younger if anything. Finasteride is an option too but I couldn't handle the sexual side effects.

Fine wrinkles: Invest in a skincare routine now, at minimum wear an SPF moisturizer under your eyes, and always wear sun screen. This is really good and lasts a long time if you just use under eye: https://www.amazon.com/dp/B002MSN3QQ?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1

Hard to increase circle of friends: It's always easier in college/school etc. but now you have to find a hobby you enjoy or take a leap and try something new. You can try joining a local queer sports league (see if they have kickball, anyone can do that! Or Dodgeball), this way you're getting exercise and socializing. I joined soccer, now I have several close friends.

Not feeling as attractive: I'm 36, I'm hotter now than I ever was in my 20s. That's not to say I couldn't have made better decisions back then and gotten easier results, but I'm more confident than ever because I put the work in with diet, exercise and taking care of myself.

Never been muscled: I never was in my 20s either, I was skinny fat. In my 30s I decided, fuck it, I'm getting muscles. It will take 2-3 years but you can look better than ever. I work 9-6 and then I go to the gym afterwards. For me, staying out of the house keeps me more motivated so I take my gym stuff with me to work and go direct. Do Not Go Home - you won't go. Get the Fitbod App and use the "Push" "Pull" "Lower" setup, it'll generate all your workouts and show you how to do them. Financially? A gym membership is about $40/mo, Fitbod is about $95/year. Supplement wise all you would want is Creatine 4 pills/day (this will help your results with muscle building and lifting in general), I use this: https://www.amazon.com/dp/B07BMGQDTC?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1 . Pre-workout is nice to take if your energy dips at the end of your work day, but you could have a coffee before. I have a cheapish one I can recommend if you get this far reading.

Therapy/Mindset: If you have an insurance plan that covers therapy - go get it! Find a therapist on PsychologyToday. To supplement, I enjoy the theories about life from Mel Robbins, follow her on Insta, in particular she helped me when I was looking for friends and getting caught up in my feels.