Hi, Yes I'm in the same boat as you - had to switch to US language instead of UK. I've been addiing the anglisised versions of words to my dictionary as I go along so it's becoming less of an issue over time. Maybe I'll switch to FUTO in order to not have to deal with this anymore. Gboard has one nice feature though in that I have multiple languages enabled so I get correct predictive completion in non-English languages.

For learning ClearFlow, I used the Games app available from the "Clearflow Games" section on their website: https://clearflowkeyboard.github.io/

I also have the issue of the thumb getting in the way so I spent a couple of days playing the games to get my layout memory up and then it became usable without frustration and I'm not looking back now although I occasionally still forget the odd letter location.