If you have questions about improving the Galaxy S3, go here...

https://forum.xda-developers.com/galaxy-s3

You will not find a better forum with more knowledgeable users to assist you.

Personally my strategy is to buy last year's phone. I just got an LG G5 (last year's $600 phone) for $200 last summer. Overstock inventory sale to make room for the LG G6.

And you can get a brand new current model phone for $100-$150 if you don't want the top notch processor and ultra high res screen and super nice cameras what not that come on the expensive phones. Every carrier has such options. They are fine for daily use and any bike stuff you want to do with them.