Each peer or full node doesn't have unique ID. Since Bitcoin uses gossip protocol, the only way to link transaction X and Y (without inspecting blockchain/transaction itself) is by sybil attack where attacker runs lots of nodes to find out which node broadcast the transaction for first time.
To determine whether a transaction originates from a specific node with absolute certainty, the nodes would have to be connected exclusively to you or have a MITM attack in place to capture the packets. Bitcoin Core does try to prevent this by limiting the connections to each block of IP, since attackers can easily purchase IPs in the same block relatively inexpensively.There were concerns about deanonymizing attacks on Bitcoin nodes operated on Tor but that is fairly old and easily mitigated by connecting only to onion nodes. If you were to allow incoming connections, ensure that Bitcoin Core is binded to your Tor instance and not your clearnet IP. Bitcoin Core is pretty good at ensuring privacy (barring user behaviors and onchain linking), there is a randomized delay with inv messages which helps to make it harder for people to determine if the transaction originates from your node.
