For me, LinkedIn seems the best channel to reach out to my network for something like this. I am not on Facebook and I don't think many people pay attention to obituarys in newspapers any more. But I think I have a plan now. I will put the instructions in an envelope and include the password plus the 2FA reserve code with it. I will put the envelope in a place in my home and let my sucessor know about it through an online service I have found and trust.
Or if the earth gets hit by an asteroid? How do you take care about your various online accounts then?
I would just pass a note to my relatives with my passwords and they then may delete accounts, or not. I rather care about my real life to be honest, and not my virtual legacy.
I live in Sweden but I found several options offered by funeral homes/ undertaker associations. They are usually called "The White Archive" (but in Swedish) and were free as well.
