My apologies, I should have made myself more clear. I understand the relationship between the client and wallet. Even if you managed to turn on minimum zap amounts I could still copy your LNURL, go to my wallet, and spam you without using a Nostr client. My point is that this is a wallet problem not a client problem.
While you may use different wallets the same can also be true for clients.
Finally, the error would not come from failing to retrieve an invoice but when you sent the zap and the wallet sent back an informative response like “This user has a minimum amount of 20 sats.”