Typically I use pen and paper, but I've been interested in a tablet or similar device for a while and am interested in what other people are using.
The reMarkable 2 seems like a really cool option to play with, but also pretty pricey for trying it out to see if it would even work well.
While it's not directly related, when playing in games, I usually use a paper character sheet for reference, a notepad for consumables, story notes, and HP, and Pathbuilder on my phone for spells.
As a GM:
I host online for friends, so we use digital tools.
As a player:
I have a tablet PC with a pen. I take notes on Rnote (free, open source.) I used to use OneNote which was great because I could search my handwriting, but I stopped using Windows.
Historically, I always used physical dice because I was playing in-person. I did my PF1e character sheets manually by writing on the PDF in OneNote, but for PF2e I do enjoy Pathbuilder to help me plan it out. For actual play, I build my character sheet in Foundry (even if the GM isn't using it for the game) just to make everything easy for me to find.