How does a whole coin work?

Is it possible to have 1 whole bitcoin, or will I only ever have enough sats to be equivalent of 1 Bitcoin, when I accumulate enough sats do they merge together to make the 1 BTC.

I am very stoned and this isn’t making sense to me because they’re essentially cryptographic keys so they’re all individual and I have lots of little pieces of the keys. Like does Bitcoin actually exist or is it just sats? Because bitcoin would be seperate from sats. The hex doesn’t alter, otherwise it would be simple to just use a public key to locate the private key pair and decrypt it…