Sometimes caching plugins harm more than help, so I would start with disabling Breeze for a while.
Using a CDN only speeds up the serving of static files (eg. JS, CSS, etc). It won’t speed up PHP processing, which seems to be your problem.
The CNAME thing is an advanced setting that requires some deep changes to your website. I’ve read about it, this will only help sites with very large traffic, I don’t think it will help you at all.
Some plugins may cause general slowness in the admin area in Wordpress, so you should check that as well.
I saw your video, this does not seem to be related to the database at all.
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