Embrace who you are, as cheesy as it sounds, and turn your quirks into advantages.
Going bald? Who cares, I started balding from 19 years old, and at 21 I had a sizeable spot at the back of my skull that I could touch with one finger without brushing against surrounding hair. Figured I'd rather be bald than looking like a haggard whimp, shaved it the same day and never went back. I'm in my 40s now.
Heavy lifting/physical work: Pumping iron isn't the only way to get a defined and conventionally attractive physique. Look into exercises to build core strength and arm muscles through calisthenics, yoga, plank holds and the likes. Work with a trainer who can give you proper guidance.
Relationships: Not every relationship is built on love. There are transactional relationships just as well, which might be frowned upon in public, but depending on the source, 30-50% of men engage in them regardless. Might work wonders for your self esteem. Of course if you choose to do so, have your local legislation in mind, travel might be required.
As for generally embracing and grounding yourself, guided meditations are pretty neat. Sometimes offered through yoga centers (it's a good combination in general and a relaxing hobby that still works on your physical limitations). I probably wouldn't do either online, having a person to guide you along for the first few times is quite important. You might also run into like minded people there, which can help to foster relationships (looking at platonic here first and foremost, an active friends group really helps to build confidence as well).