I get that. If you do decide to go with your initial idea and are looking for simplicity rather than having them download a wallet to transmit the transaction you could simply point them to a website to broadcast such as

The Mempool Open Source Project®

Explore the full Bitcoin ecosystem with The Mempool Open Source Project®. See the real-time status of your transactions, get network info, and more.

Another idea for you is that you might want to make the wallet that the funds are sent to be a bip-85 derived seed from your main wallet. That way if you transmit early as long as you have access to your initial wallet you are not at risk of losing funds.