Have a look at and do a copy of the default one, so you can adjust it to your requirements: V1.1.0 Templates - Where are they now? - #5 by Lupu
crontab -e -u admin or in backend on crontabs
that’s a question for @lupu but probaly you’ve still somewhere set php-7.3 as default in the server settings, that’s why it’s greyed out.
Increase the max amount of backups under user → packages.