just don’t. that’s plain wrong for files.
while I undertsand that as motive, I am sorry to say, hestia probably will still be the wrong thing for you.
if you are dependant on things like a file manager and are not able to fix permission issue with your system admin powers, I am afraid you will run into more issues. HestiaCP is no replacement for admin skills and basic linux knowledge, but intended to complement to that by making recurring tasks easier.
don’t get me wrong, I understand everyone needs to start somewhere. however hestia is going into another direction and expects a minimum level of knowledge and ability of handle things yourself. otherwise you are better of with shared hosting or cpanel and the likes.