That is a challenge. Hardware wallet is still the best choice in my book, I would share your seed phrase with your children or person inheriting your wealth if you trust them and when they are old enough.
I also use unchained capital which is a incredible multisig service for inheritance management. nostr:npub1m6y9qq06c74trgs60ya320pgmhz6099grra5lw04akyuxvcz7lvq9ue2p9 can help you get signed up if you’re interested.