I have the same issue (blank pages) on my website. I have tried all the above but nothing happened. I think my problem started when I cloned my theme (to use it on a different storefront), used the clone theme as a default but then I decided this clone is no longer needed, so I moved back to my original theme and deleted the clone theme. I lost 2 of my pages now as I can see only blank white.
I increased memory limits on config.local.php, tried all the above but nothing happened.
Any help would be appreciated!
When you deleted your clone theme, did you do this: