I guess my question is, why does it matter? If you're gone, you're not going to know what is happening, and your name will eventually be forgotten to time anyway. So does what others think after you're permanently gone matter?
Agree, unless you have something that would hurt or incriminate someone you care for, what difference does it make if someone reads your email.
However, to be safe whilst alive (if you care), I would suggest creating a protonmail account that you use only for ss and ctb related things. Passsword doesn't have to be crazy hard, just different enough from your normal ones that no one would guess it. Same for the username. Would recommend doing the same for reddit, discord, and telegram if you use those. Telegram offers secure two-way messaging, so if you use that with ss friends, the messages will auto delete after a while, and they get encrypted.
Few other things: Remove fingerprint unlock from your phone, and change your pin if anyone knows it. That will secure your phone, and no one will be able to get to the contents of it. You won't need to reset the phone before you ctb.
Same for your PC. Do a full-disk encryption, and set a startup pin/password. That provides redundancy in securing your comp. Can't get into bios to change settings - reset the bios and the encryption pin for the hd is lost - data is useless. And if you pull the hd, it's encrypted, and without the pin, data is useless.
Edit - I mentioned fingerprint unlock. Should have said remove all biometric unlocks (fingerprint, face, retina, etc...). These can be used after you're dead to access your device. Same for pc/laptop/tablet/etc... If you have any way of unlocking other than password or pin, remove it prior to your attempt. May not be a bad idea to remove them before if you are worried about parents/friends/authorities accessing your device without your permission. Only takes one person stronger than you to force your finger onto a screen.