Thats a bad move to begin with as that would imply you dont have a certificate on your server which basically means your site is still insecure.
A host should generally not sell certificates these days. I’d consider moving host in your case.
A 521 basically means Cloudflare cant reach your server → Community Tip - Fixing Error 521: Web server is down
That could have different reasons. Maybe Godaddy is rate limiting your domain which means Cloudflare connections would be actively blocked by them if your visitors exceed a certain number, but that is only speculation at this point.
It would, but you dont need to pause Cloudflare. You can simply use the hosts file to map your domain straight to your IP address.
Whats your domain?