How to avoid using the ai built in Ubuntu ? Just switch to a better distro.

Why not just add mail address to your regular contacts ? Simpler, safer.

I don’t know for Brazilian but for me in french, I use a variant of the french keyboard that include all necessary accents on the keyboard and not as alt-codes. Maybe there is something similar in the settings.

You can use dedrm plugin in calibre to remove the DRM on your ebooks. You just need to download them on your computer, like using an old version of kindle.

If you want to buy more recent ebooks, as someone else said, the DRM cannot be removed now, so you should download them from kobo if you want to still be able to download and remove DRM.