Thank you for your comprehensive answer. How do I delete a transaction at all until it is confirmed and if it is RBF?
You can't delete a transaction once it's broadcasted (doesn't matter if it has the rbf flag or not). You either wait untill it's confirmed or untill most nodes dropped it from their mempool, or you bump the fee (create a new transaction to replace the previous one, but not deleting it).
Why would you want to delete a broadcasted transaction?
In the future, I would just like to have this opportunity. For example on Bitcoin Core this is available and you can cancel a transaction that is still hanging in my pool and has not been confirmed