How can I become 100% owner of a bitcoin node?

How can I become 100% owner of a bitcoin node without depending on bitcoin core, umbrel, etc. For a cryptocurrency project I need a bitcoin node that I own to be able to receive and send funds from various users. The idea is not to depend on any third party.
I have read that I should write it on C++.
Is this correct? How can I do it? How could I have it later on a server to create wallets for the users?