It kicks in about 10-15 seconds after initial launch of the browser, and basically churns it to a near halt for at least 30 seconds before it becomes usable.

Could be that this tablet of mine provokes the behavior by having a slow emmc that is nearly full, but it has resulted in me minimizing my use of a browser i have been using for close to a decade across various computers and operating systems.

And no, it has nothing to do with extensions. I still see it with no extensions active. Heck, i even see it with guest mode active.