Best practice: hold your BTC in some type of multi-factor wallet

Larger stack: consider a collaborative custody multisig with casa, unchained, nunchuk, liana, etc. All have pros and cons, but all greatly reduce risk of total loss upon death. Don't try DIY multsig, most ppl with mess it up

Smaller stack: poor man's multisig (singlesig + passphrase). Share seed phrase with heirs, passphrase with executor (someone not an heir). Again, pros and cons, but pretty simple so reduces risk of catestrophic loss.

Don't rely on treasure maps, letters of instruction, those fail WAY more often than you think.