This, a million times. Tech nerds love cooking up elaborate technical solutions to this problem (I’ve seen it here in several threads over the years) but completely ignore the legal requirements and expectations around establishing next of kin and executing probate.

My recommendation always remains the same: don’t over complicate it and work with the existing societal processes. Society deals with people dying all the time. All major companies, industries, etc. have means for dealing this which have established legal precedent and won’t get anyone in the shit by following them. Let those processes unfold and instead focus on providing your loved ones with the means of having what they need to do so.