I use LastPass’s Emergency Access feature for this.

You can designate people who can access your Vault, after a certain waiting period. If they request access prematurely, I can revoke it during the waiting period.

There are written instructions for my next of kin on what to look for in the Vault.

The main difficulty is if my next of kin forget their LastPass master password.

I’ve been thinking of distributing a key via a set of USB stick using Shamir’s secret sharing, with written instructions to use them to recover a backup of the Vault kept offline… but have not gotten around to this.

One could put an unencrypted usb in a bank safety deposit. I kinda get a kick out of the notion. But yah Shamir’s seems underused.