While I'm not sure if this'll help, but...
First, I define Anime as: Animated material
developed and primarily intended for a Japanese audience.
Notice I didn't include produced. I kept that out to keep productions where a Studio is a co-producer in a project, but it's intended primary airing isn't Japan. I know that also gives some grey areas too, but at least allows a reasonably solid base line to work with.
As to G1
Transformers being Anime or not? Technically, even by my definition, I'd say no. While the toys G1 was based on were of Japanese origin, the background and characterizations were developed in the US for a US audience. Noting that, I would make an exception for the Japanese-exclusive series based from G1 though. Youtuber Chris McFeely, as part of his "The Basics" series, just covered the
Japanese TF Series. It's worth watching.