I kind of had this in my late 20s.
I'm now 30s, work a 'normal' job and live a 'normal' life, but secretly I am comfortable, i.e. when people talk about saving for retirement and ask what I'm doing for etc, or cost of groceries, I just don't really join in, without outright lying.
Think about other people that may come from a normal background but become very wealthy in early 20s, e.g. actors, artists, footballers... Suppose it's quite similar to that. There's lots more people like that than you can maybe see.
Do you have any peers that work alongside you? That had a comparable journey? The truth is that you'll probably find more in common with them. A lot of people think they need to stick with their childhood friends etc, but they really don't, it's not a law. If you're extremely driven, you may find it hard to find touchpoints. Most people are happy living like everyone else, doing things 'because it's just what everyone does', and that's okay, too. But you might have to accept it's not you.
It may feel like 'I am only x years old and I've done what I wanted to do with my life, so now what?'. Most people won't be in that place, they'll still mourn lost dreams/ goals in their 30s and 40s. I don't know whether it was your goal per se, but if it was, you need a few years to recalibrate and figure out what your new passion is.
I'd say explore, read books, watch documentaries about causes, think about things that make you happy, or angry, or feel something. Can you use your money to benefit the community/ world? For example, mine are sustainable fashion, better quality, healthier food available to all, and a few others.
If you are self-made, what about kids in your community? Do they have opportunities to follow your path? Did you benefit from something that others might find useful?
You say about being a landlord. Do rental properties fill your heart with joy? Do the people living in them benefit from what you're doing, for example? You're kind of set for life, provided your money is wisely invested and protected, unless your goal is to become much, much richer. So why not lock some of your money away for a rainy day, and make investments that actually fill your heart with joy, make your city a nice place to live in, benefit someone's life etc?
Most importantly though, look after your body, your mental health etc. You have access to things that other people won't have access to. I see a lot of wealthy, sucessful people suddenly tap into extreme wellness, alt medicine etc, when they are 50+. They almost have that lightbulb moment about what life really is about.
You're on here and clearly feeling lost and dissatisifed when society tells you you should be living the dream. So take time for yourself, get therapy, get an amazing wellness club membership, enjoy some of the joys of life that you can afford. Get some spark back.
Read about other people in a similar position. Emma Grede springs to mind immediately, but there are many others.