I spent over a year working on this from building up a collection of pets, learning the strats, and slowly piling up wins in the AMM. Today, I finally completed it, and the Trainer title is mine! I recorded the last 10 wins out of 1000, compiled them into a video and posted it:
Video of last 10 wins for my Trainer title!
https://nofile.io/f/Dej1pkMhGtO/trainertitle.mp4
As it turns out, the most successful strategy was landmines. A LOT of opponents tended to build teams that involved swapping pets in and out for one reason or another. So I often went Blue Clockwork Rocket Bot and Rotten Little Helper together. Dropping landlines all the time absolutely played havoc with a lot of enemy strats and gave me an edge. It can be countered but doing so invalidates a lot of strats people would otherwise use.