First, you sound depressed which is common when you reach a point in your life where you realise that you might not actually be living true to yourself (that’s the feeling lost part - something in you is making you feel acutely that you are not doing what you really want to be doing). My gentle advice is to take care of that because it’s probably dragging you down. You should probably talk with a therapist and start working out if you don’t already.
You also sound dangerously in need of self love. You obviously haven’t achieved nothing. You have held jobs in widely different environments. Tried to start a company multiple times and put aside a significant amount of money. Be gentle with yourself and try to cut yourself some slack.
Then I think you should realise you are not getting old. You are getting older like everyone else on this planet. There is no magic cutoff when you can’t do things anymore (I mean technically you might get unable to do them physically but you are still far from that). Do what you want. If you feel like going to festivals, no one is going to stop you. Some judgmental people might find it weird that you do things they consider inappropriate for your age but thankfully you don’t really have to care about judgmental people.
Finally, there is no miracle solution to feeling lost. You will have to ask yourself some hard questions (but a therapist should help you if you want to and need to) and figure out what you actually want to do with your life. Good news for you is that you are both single and somewhat rich. That gives you a lot of freedom.