We know that bitcoin is generated by what we called "mining", but is there any process that is more competitive and decentralized to generate bitcoin?
There are no other ways to generate bitcoin, if by generating you mean creating new coins of course that are not yet in circulation. If you just mean getting some bitcoin to yourself, then there are plenty of ways to do that, since we already have a decent market where we can transact bitcoin, either by direct exchanges (where you buy and sell bitcoin with other currencies, wither with fiat or crytpo), but also by selling goods for bitcoin, or simply working for them.