Formatting lost, can’t save edits

I posted this blog recently, and the formatting I see when editing is not what gets posted.

I tried installing the Preserved HTML Editor Markup Plus plugin. It did not solve the problem.

I tried creating another post last night, using the new-to-me block editor. My site would not save the draft. I tried creating it multiple times.

Today I can’t save edits to existing pages, even when I switch over to block editor.

I’ve removed the plug in, with no results.

The page I need help with: [log in to see the link]