WordPress nonces are wrong and not working?

I really don’t understand what is happening with WordPress nonces, i think they’re wrong, or they’re useless.

I always have troubles working with that nonces, WordPess never been able to check one nonce successfully, i will put here 2 cases in which the nonces aren’t working, in all cases i tried to maken aj AJAX request:

CASE 1:

In this case i tried to use wp_rest nonce to verify it:

PHP (plugin.php):

JS:

It only works when the user is logged in, but i’m not using users on my website, the only user is admin, so, it doesn’t work for guests users (And i need to works for them), when is a guest user, it returns: rest_cookie_invalid_nonce 403 error PD. I don’t put the code of the ajax functions ’cause it doesn’t even get to run them

CASE 2

So i don’t want to put more code here, but, for this case, in wp_create_nonce function i change the wp_rest string for any_valuestring

In the $.ajax call y delete the headers option, and y pass the nonce in the data option as “nonce_field”, and in my rest functions i do this:

And it always returns false, the nonce never pass, and also happens with:

So the nonce never is true, and i don’t know why, it should be an WordPress issue, i’m using WordPress 5.5 (The most recent version) so i think if it’s always return false then the nonce in WordPress are useless

Or can you help me what i’m doing wrong? Thanks a lot!!!