I'd VeraCrypt your entire machine. That way if you do leave us, the key dies with you and your data (at least your local data) is useless. On the other hand, if you get saved and/or don't go through with it you can still get back in. As far as online accounts go, I'd recommend closing all but the absolute essentials well in advance (up to 30 days in advance in some cases!). That way there's no question of people gaining access to anything.
As for phones and tablets, if it has boot-time encryption (EG Samsung Knox, whatever encryption Apples have etc.) I'd recommend turning that on too, and setting actual passwords for unlocking, no face ID, patterns or fingerprints. Law enforcement can't break most phone encryptions without some major effort (and even after disassembling your phone in some cases), so that should prevent your family, friends etc. seeing something you'd rather they didn't.