2. Federated learning comic: https://federated.withgoogle.com/ (I'm personally not a machine learning expert and I found this pretty informative while being accessible.)
Disclaimer: I am a Google employee, my opinions are my own and I don't claim to speak for my employer.
The question is a bit foolish: "Is [insert softkeyboard application here] basically a key loger?" -- well, the softboard itself is the key generator, if you want. By definition, it has control over all input. By definition it can do anything it wants with it.
If you don't trust Google, don't use Google software. A LineageOS installation doesn't come with the GBoard but instead the plain Android softboard which is the same without the fancy features (i.e. lacking Google search, image search, etc.).
Anything that’s from an advertising company should be considered suspicious, just like you should consider it suspicious when an alcoholic wants to “help” guard a warehouse or truck full of booze.
1. Federated learning paper as relates to keyboard [PDF]: https://arxiv.org/pdf/1812.02903.pdf
2. Federated learning comic: https://federated.withgoogle.com/ (I'm personally not a machine learning expert and I found this pretty informative while being accessible.)
Disclaimer: I am a Google employee, my opinions are my own and I don't claim to speak for my employer.