How to speed up old iPad 2 (maybe replace iOS?) My old iPad 2 is unusably slow, even just to browse the internet (such as by using Google Chrome). It's nearly a piece of trash at this point.

I've tried a complete factory reset multiple times.

If I'm willing to do pretty much anything to this iPad at this point (jailbreak, roll back to previous iOS, or install a different operating system entirely, etc), what can I do so that I can browse websites easily and quickly?

I'd love to use the latest version of Google Chrome or Firefox if possible, but at this point I don't even really care, and I don't care what OS I use either.

P.S. The back of my iPad says A1395 16 GB, which means it's the "iPad 2 (Wi-Fi)" from 2011 according to Apple. It's running iOS 9.1.
The only practical thing that might help is if your battery is failing - putting in a new one might pep up the processor.

The actual browser is going to be hard to make faster and jailbreaking and running another OS is going to be likely far less optimized than iOS 9 is already for that architecture.

Your main help for browsing websites quickly would be to select websites that don't use javascript much or block that from running and consume text / html / light css.