Interesting. Uni means handwritten notes? I dont like them as they are not searchable. Dont know any note taking app that would overlay OCR text.
XODO pdf can do a lot of PDF editing, drawing etc. Works offline and is the least bad proprietary one.
Krita works well on Android, there are some issues but they can be worked around.
I found this review interesting by an artist. He uses Google Android (which has more custom Tablet stuff afaik) but still the drawing experience wasnt great.
Stuff like palm detection doesnt work so you might want one of these gloves.