I don't know what Levvy.Fi does, but anyone knows which UTXO they can spend by looking at UTXO's address -- they can spend it when:
it's a hash of a key (wallet) they control, or
if it's a hash of a ...
I don't have a Ledger so I'm not quite sure. But here's how it usually works:
Your wallet has multiple addresses
You can use any of them to receive ADA
You can send ADA from any of the addresses as ...