The address is the owner EOA
Resolve an owner address and you get that same address back. Nothing is derived, nothing is counterfactual, and an account holds its balances at the address the user already knows.
Account model
An account is the owner EOA itself, activated per network by an EIP-7702 authorization.
What the model means for your client
An account is the owner EOA itself. There is no separate contract address to create, fund, or deploy.
Activation is an EIP-7702 authorization
The first operation of an unactivated account carries an authorization tuple that points the EOA at the UGTP account delegate. The prepare response says when one is needed with authorizationRequired and authorizationNonce; attach it to that submit and never to a later one.
Activation is per network
An authorization is signed for one chain, so activating on one network says nothing about another. GET /account/delegation-status reports every network separately as activated, not_activated, or unsupported.
Avalanche C-Chain has no delegation
Avalanche has no chain-level EIP-7702, so accounts there are never activated and delegation-status reports unsupported. Its operations travel the executor rail instead, and the API contract is otherwise the same.