I’m looking for information around the founding of Ethereum and ETH 2.0. If the blockchain can’t be hacked or altered, how does Vitalik have the authority to branch the chain ? What mechanisms is he using and what mechanisms prevent someone else from doing so?

I’m looking for information around the founding of Ethereum and ETH 2.0. If the blockchain can’t be hacked or altered, how does Vitalik have the authority to branch the chain and what mechanisms prevent someone else from doing so? Are we putting faith in what just a few people at the non-profit do and bank on them to make the proper updates?