Question about studying on the go with mobile apps

Long story short, I'm trying to find out if there are any good mobile apps for learning GTO strategy. I played online regularly between like 2015 and 2019, but haven't played much since and would like to catch up on my theory. Is there a phone app that would be good for learning GTO from the ground up?

I know solver and database analysis should be the main learning tools, but I'm often pressed for time and would like an option that doesn't require my laptop every time.