If you prefer some story-heavy games, you can try Eastward. It has gorgeous art style and controls and UI are a great fit for handheld devices such as Deck and Switch. It takes ~15% battery a hour and can be completed in 10 to 15 hours.
If you're fine with longer games which will take 45-70 hours total, try some 2D JRPGs like Trails in the Sky FC (which also has nice touch input in menus!), Trails from Zero and Chained Echoes. All tree aren't battery-heavy at all.
Thank you for contributing to what will become "best practices" for any new instance when the surge of new users from Reddit (as well as spambots) subsides and the situation becomes less chaotic. I hope other instances which blocked yours over the spambots reconsider their decision.