My bad, English is not my mother tongue. Tuxguitar has also for chords and yu can add them to pdfs when printing.

Tuxguitar has a fork with update development (android version included), and for looking up chords (guitar) you can check there is “fretboard” in flathub.

I guess you are looking for an android app? I use Oss Document Scanner, and I am relatively happy with it https://github.com/Akylas/OSS-DocumentScanner

I combine OnlyOffice with its DrawIO plugin. Drawio is also cool standalone app for diagrams I can recycle) that also has tex typesetting for formulas.

Onlyoffice Is a bit annoying sometimes with sizes when going back and forward to powerpoint (common computer for presenting) but is more compatible than libreoffice in my experience. Biggest drawback is the lack of master slide mode, but I typically use the standard one.

Amazfit bip have always on screen. You can use it with gadgetbridge in android and forget about the official app