ultome if disabling the network is not enough for you (its not for me), an option I am considering is installing google play and gboard and a whole host of other google and nongoogle apps (recorder, speech services, camera, phone, sms, contacts calender, etc.) And letting them update and get all their features functional, and then cut internet access to all of them at the same time permanently, including google play itself. This way i think all functions are retained and i can be sure of no data leak. Downsides are no push notifications on this profile and no other google or corporate apps to be installed with internet access after, never to be reconnected to internet without profile reset (for those apps).
If you are ok with the downside, this is i think a doable and good solution.
missing-root
I have been using open board without auto correct and suggestions and recommending the app. However after using it for 1 year i have to admit the typos and fixing them are too much of a pain and i just cant type fast. I am now looking to switch to one of the "pro level" keyboards like gboard or swiftkey.