Media library issues

For the past few releases, there has been, what appears to be a bug with the media library. It continues with version 5.5.1 and PHP 7.4.9. When attempting to insert media in a page. If I click “add media,” I am presented with the files currently in the library. If from that screen, I click, “Insert from URL,” I get a blank screen. Likewise, If i attempt to customize the Theme and add a logo, I can select an image from the Media library, but when I click Insert, It takes me to another blank page, with no way to proceed with adding the Logo.

I installed and ran the JQuery Migrate Helper, but nothing shows up as an error. All plugins and themes are up to date and compatible with WP 5.5.1.

These issues happen with both a single site install and a multisite install, and several different themes. Likewise, with the latest versions of Firefox, MS Edge, Internet Explorer and Chrome. It happens on all tested devices including Win 10 desktops and laptops and mobile devices running Android.

I reported this as a bug, but the response was to check the above and post a support message, so it seems that they don′t think it′s an actual bug.

If you have any ideas what, besides the plugins, themes, platform, browser or scripts that might be causing the problem, I would appreciate the feedback. I can work around the problems, but these features are valuable and I would like to be able to use them.
Thanks