I've followed the steps outlined to connect my Drive account with Adobe Acrobate Reader on ipad, After 10 minutes of loading, I was finally able to connect my Drive account to adobe reader in the adobe reader app, but upon trying to open actual files from my Drive, none of them opened (it took 20 minutes to load, and then the screen just closed and went back to the homescreen for adobe reader and never loaded). I've deleted the app, reinstalled it and restarted my iPad but I still get the same issue.
Additionally, I try opening the pdf file from the Drive app itself (versus opening it from adobe) following your steps outlined in your guide, and the file will open, but I can't save it back to Drive, it only saves it locally.
Please let me know if there's anything that can be done to resolve this issue. This issue never occurred when I used Dropbox for a year, but it seems to be an issue with Google Drive connecting to Adobe.
I have also just tried this with OneDrive as well, and the exact same issue keeps happening with the exact same wait time, so I can open/connect nothing to the Adobe app except for dropbox files. Hopefully there is a fix for this.