Hi there, fellow Vietnamese.
I have been struggling to find the answer for that same question and after some serious contemplating and self-reflecting I have come up with the best solution for myself, hope it'd apply to your case.
Committing to a company!!
Yes, it sucks to work for someone else, when you know fair well that you have great potential and you can do and achieve so much when you have that sense of freedom. But hey, you're only 22 years old. Even tho you would love to believe you are wiser than most people your age, there are a lot of things you still need to learn, develop (mentally, spiritually, financially, heck even physically) in order to achieve that ultimate goal "being self-employed and eventually reaching financial freedom".
You are still contributing greatly to the society while working for that start-up, so why not? Taking that 2-3 years there as an opportunity to grow and prep yourself for that future you have been dreaming of.
Hope this help you somehow haha. If you live in Saigon or Hanoi let's have some chats after this sucky quarantine is over! It's nice to finally meet someone here who's Vietnamese :))