Can't log into my dashboard

My site is at https://www.allenbyparents.com. I can’t access my dashboard anymore and my theme seems to be gone. My content is still there, though.
I updated the Primepress theme a few weeks ago. After the update, I had to recustomize my settings. No problem. But my WordPress files are in a subdirectory called blog1 and my domain would no longer point to that directory. So I did this, which I had done the first time I installed this theme. This time, though, I was not able to change the text in the “Site Address URL” box. It would not let me. It gave me warning about changing this.
After I logged out, I was no longer able to access my dashboard. When I go to https://www.allenbyparents.com/blog1/wp-admin I get a 410 file not found error.

Also, if I go to https://www.allenbyparents/blog1 I get the latest content but not the PrimePress theme. All my pages are text only with no formatting.

I’ve tried troubleshooting with my host with no success. My database seems to be fine. I tried repairing and optimizing it through phpmyadmin. They suggested I try some WordPress forums.

I’ve tried removing my edited index.php file from my main directory. When I do this, I see my old home page from a few weeks ago with the PrimePress theme working only for the home page. It’s not the latest content, though. When I re-uploaded the index.php file to the main directory with the last line changed to say require('./blog1/wp-blog-header.php'); I got the page you see now when you go to my site — just unformatted text, no PrimePress.

I’ve tried disabling my plugins but that did nothing.

Is there a way to change my theme via ftp just in case the theme is causing the problem. Then I could access my dashboard and see what’s going on.

My other alternative is to deactivate WordPress and reactivate it, but I don’t want to lose my content. I’ve never reinstalled from a backup before so I’m nervous about doing that.

Any suggestions?