Sporadically Can't login in or access pages in dashboard

Hey everyone,
First time posting on here.

I’ve been having problems with my site. I’m not a coder so I’ve been hiring people to help me with this issue. I had a site with some pages on it and decided to move some of the pages over to a new domain. I had my developer do this. He ended up copying the entire site over not just the pages I wanted. Which is fine I guess but just added it for info maybe it’s related to my issue.

So I had everything copied over to my new site and weird things started happening. I’d try to access the wp-admin login page and it would be a blank white screen. Then I’d contact the developer and he supposedly did something that fixed it.

This happened a couple other times where I didn’t contact the developer and within a day I was able to login in. The same thing will happen with pages on the dashboard. I just tried to access my plugins page and checkout page and I get a blank white screen.

I’m not sure what’s going on or what’s causing this. Bluehost is my server. I don’t know if it’s a server issue or my WP backend having an issue. But I’ve went through several developers and feel like I’m not making any progress and I need to get this site working.

Anyone else experiencing problems like this? Any idea what it could be?
Thanks,
Mike