Does the new transaction in RBF have a different txid than the aborted transaction? So isn’t that basically creating a new transaction?

Essentially, this is what it is. The RBF transaction is simply a new and separate transaction.

But the RBF aspect, the rules associated with it, are important. A full node maintains a list of transactions (called a “mempool”) that it expects to confirm, with applicable rules for entering the mempool and being forwarded to other nodes.

One of these rules is that, in general, an existing transaction in the mempool cannot be replaced by another transaction. When RBF is enabled on the source, it is allowed under certain circumstances.

In short, while alternative transactions are in progress. valid Regardless of whether the original selects RBF or not, this does not necessarily mean that it will select RBF. accepted It is propagated to miners through the network for each node.