See the picture of CPU inside Poke 4 Lite at this site, could be the same as Leaf 2:
club.dns-shop.ru/review/t-81-elektronnyie-knigi/76304-obzor-elektronnoi-knigi-onyx-boox-poke-4-lite
My favorite browser is Bromite. I'm not sure if it needs Google services for working, but it still works after I have disabled all Google software at device. Well, Google TTS works too.
My second choice of browser would be Mull from Divest OS. It is "de-mozilled" Firefox
I haven't used firewall on Android for years. On AFWall+ I have chosen "Allow selected", then cleared all selected and marked programs, that I wanted to get access to Internet. Then I have executed "Apply" from menu (easy to forget). I hope this is OK. Selected apps work and router doesn't show any unwanted connections form reader.