Problems logging into my WP site

Hi,

Having a bad week with my WP sites and tearing my hair out.

I have a site at:

https://domainnamechecker.com.au

Which appears to still be working fine but I just can't log into the admin area or even bring up the login screen.

I don't know if I have been hacked or not but it is very strange. I do have the DNS with cloudflare but had been fine.

I have tried all the obvious urls - /wp-admin/ /wplogin /wp-login.php etc

I still have FTP access fine.

What can I do to get the login working?

Considering moving all my hosting to a managed WP host like WP-Engine - any thoughts on them?

Dale.