I was thinking of doing it myself and wrote a Python script that XORs two seed phrases, but left it at that for the time being. It would have to be run on a machine that's not connected to the internet and an OS booted from a USB stick, like Tails, to avoid malware. Hardware solutions are surely preferable.

SpaceHodler

bitcoin

multisig=🤡 singlesig=🍼 shamir secrets=🪤 seedXOR=👑

tenderscore

Yes good explainer Space. OP was right as well about the optionality, decoying, and plausible deniability. I think it allows for this better than any other solution. I don't know, I personally think it's very underrated, because of what you can start building beneath the original seed and it's 2+ XOR, which is perhaps unexplored. But sXOR it's also relatively new; 2021 or so, and the only hardware wallet that supports XOR computing of the original seed is Coldcard. We need more.