I suppose if you were willing to add complexity you could have multiple signed at different rates.
Discussion
I’d want to reduce complexity, so I’ll go back to the drawing board
Have you looked in to a Bitkey?
They have tools to help with inheritance.
https://bitkey.build/inheritance-simplifying-the-transfer-of-bitcoin-to-future-generations/
I generally wince at 3rd party assistance here, but I’ll go read it all and try to understand the risks. thanks
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 https://mempool.space/tx/push
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.