Anyone know how to disable this popup correction thing?

I don't know how to turn it off, but I do have a couple of suggestions that may mitigate it. Can you install the language that matches yours so that it isn't confusing properly spelled words in your language as being misppelled in English? That would be under language and input in settings.

Another option is to slide your finger across the space bar to move the cursor to the location where you want to make a correction instead of tapping on the screen. It should move the cursor one character at a time.

 

Go into the gboard settings menu then select the text correction section. In there you should be able to disable auto correction.