Thanks @nikgid
I intentionally bought the device as a gift for a blind friend, but the crippled Android by Onyx prevented me from activating TalkBack. At Arta they couldn't or wouldn't help me. I think they never had blind people on their radars as an important marketing target. Maybe eventually if results are good and the word spreads ...
Today I rooted the device as shown above. Then I installed "Settings" by gabenative from the Google Play store along with TalkBack. SU access allowed me to activate Accessibility Settings in "Settings". Works fine. And the touch inaccuracy at the bottom of the screen isn't an issue for a blind person.
I used to love FBreader a lot, but again they crippled the user interface and made it a PIA to use. So I bought MoonReader+ and installed it. Happy again. Text rendering and zooming of PDF files works like a charm with MoonReader+. Their TTS interface allows every language and every TTS engine available.
Now I'll install a launcher and give it to my friend for a test. I'll keep you updated here:
https://www.mobileread.com/forums/sho....php?p=3022268