A paper-only journal would defend against the state, but not against people you live with. A digital journal can be encrypted, but an intelligence agency could potentially gain access (like, them reading your anti-government rants that may involve violence… that sort of stuff).
So… how to defend against both threats?
(Also, I just realized, paper journals cannot really be easily backed up…)
Obsidian stored in Veracrypt. Bonus if you get security keys for veracrypt, either as piv cards or using long passwords only on the key.
Standard notes doesn’t require an email. Just make a private username and password.
Protonmail and mailbox.org support pgp. Protonmail pgp is quantum resistant. Grab a public key and write emails to a free account.
Honestly though, get a fire resistant bag or safe and a notebook. No bit rot. No hacking.