Hello, if I have several different UTXOs (mixed) in one wallet and I make a transaction, could the receiver see all of my UTXOs in the wallet or just the one they received? Thank you!
They will see only the UTXOs they received. If, however, the change from the transaction should go to an old change address then you will effectively relate this transaction to any prior transaction using that change address. In general new change addresses should be used but depending on the size of the change you may not want that if it will create dust UTXO (a UTXO whose cost of spending at current txn fees exceeds the value of the UTXO).