I've been trying to get "Site not secure" for weeks now, and nothing. Once I do, I'll report to Plarium which file to fix. Nevertheless, the warning is irrelevant. What is "not secure" is the loading of some third party site, likely related to ads or analytics. All that needs to be secure is secure.
As for your other problems, I am experiencing none of that. Some of these sound like your own computer issues. This game is a hog for resources and I had plenty of those problems until I upgraded my hardware. Sadly, I don't expect Plarium to ever improve the game's performance. I'd suggest turning off animations, to make it a bit easier on the game to run.