I recently recovered from a very long time where a number of my sites would not work.
My problem started when I upgraded my hosting account and the tech merged 2 accounts onto one domain / sub domain file tree.
I repetedly gave up because I simply ran out of time arguing that they should fix the mess.
Finally I asked the host to erase all my files and start over. They instead switched me to a new server, which helped, but since there were still remnants of old files present on the old server and they gave me incorrect path names, printed in the new service email, still resulted in 2 more weeks lost. This was a big ordeal.
So my question is, for big problems when is it s good idea to Factory Reset your cpanel account as discussed here? https://www.pickaweb.co.uk/kb/factory-reset-your-cpanel-account/