Videos in Safari are freezing

As subject says - videos freeze intermittently in Safari; videos in Twitter, YouTube, etc. Moving the cursor helps but doesn't solve the issue.

I've done a full safari reset per some recommendations I found earlier:

Remove Safari’s configuration folder:

Remove Safari’s window state:

Remove Safari’s application caches:

Remove Safari Cookies configurations:

Remove Safari’s preferences:

Remove user plug-ins:

Remove global plug-ins:

(left this one behind - iPhotoPhotocast.plugin).

I downloaded the EtreCheck app and ran the report, as attached via Additional Text.

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