This topic has already been discussed a lot of times here in the forum. Personally, what I do is leave everything like passwords, seed phrase, private keys, and even my bank accounts in a notebook, and I also have a soft copy offline on a flash drive for backup. This wasn't for sure the best method for investors, but atleast have a way for them to access it if something happeneds.

Still I think the best way was to be open about it on someone that you really trust, like for example for spouse, I already explain it to him even though she wasn't really in to Bitcoin or cryptocurrency and doesn't know a thing, I told her that everything that she need is on my notebook to access my Bitcoin and she can withdraw it or sell if if I die, I think being transparent about finances was the best thing to do, so that they are aware of it, and it wouldn't going to be a waste.