waxwing on Nostr: Is there any way, with Bitcoin Core, to simulate (on regtest or signet), purging of ...

Is there any way, with Bitcoin Core, to simulate (on regtest or signet), purging of an in-wallet transaction from the mempool?

(Working with bitcoind via the RPC; this is for Joinmarket)

From years ago I vaguely remember something called 'zapwallettxes' or similar. But apart from that I'm not sure how I could do it.