You may be overcome by events... mostly time, particularly since they’re now selling the S9 tablets. In fact, I’m having some difficulty in trying to figure out the chipset you’ve got, but it’s at LEAST 8 year old technology (possibly over a decade... congratulations in getting this much mileage out of it).
But as others have suggested, there is no ‘upgrade path’ available for a tablet... it is what it is (can’t even add memory easily at all, but certainly not a new processor).
I see that Samsung’s website is selling tablets beginning at $99 (Tab A7 Lite), but be wary: the chipset on these lower-scale offerings isn’t going much better. The high end of their lineup starts at $1100... something like an S7 is still in the 500-600ish range, but would at least run fast enough to be an improvement.
Not the answer you wanted, I’m afraid. It’s just a matter of whether you can tolerate the current performance (and since you are asking, I suspect you’ve reached that breaking point).
Thank you