@jlfranklin mentioned Database SSL Check in https://github.com/backdrop/backdrop-issues/issues/4772#issuecomment-778.... That is a D7/D8 module, and it could of course be ported to Backdrop contrib, but it's only a ~40-line implementation of hook_requirements(): https://git.drupalcode.org/project/database_ssl_check/-/blob/7.x-1.x/dat... ...so I believe that it could be a nice addition to core, as part of #3624.
I've installed the module in Backdrop (simply modifying it's .info file), and this is what it adds:

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@yorkshirepudding, In the end I fixed it by deleting the config/active folder contents, copying the config/staging/ files into config/active, importing the database again and clearing the caches...
Importing the staged config throws an error: another field with the same name already exists
Thanks, I have to go out now, I will try later on and report back
Importing the staged config throws an error: another field with the same name already exists
Hi Francis. Yes, what config do you have in staging for it? You might have configs like: field.field.field_video_embed field.instance.node.page....
Importing the staged config throws an error: another field with the same name already exists