Updating admin user e-mail, when you only have MySQL command line access: UPDATE `wp_users` SET `user_email` = 'INSERT_MAIL' WHERE `ID` = '1';
If you are unable to post in Wordpress, you might want to add this to your wp-config.php: define( ‘WP_MEMORY_LIMIT’, ‘256M’ );
Also install classic editor and disable Wordfence completely (look in .htacces) and remove or rename .user.ini
There are many backup solutions out there for wordpress sites.
For example these plugins:
UpdraftPlus can be connected with dropbox.
You might also want to build your own backup routine with cronjobs on the hosting server.
Remember to backup!