Keep the home screen to one row of essentials. Remove widgets. Turn off all nonhuman notifications. Use a simple timer and stop when it rings. Charge the phone outside the bedroom.
As someone who's been painting for years but remembers being a total newbie,, I get your struggle with fast-drying paints and limited space :) Acrylics are perfect for mimicking watercolors if you add mediums or water to slow drying and improve flow and and there are affordable sets under $that model that come with a variety of colors, often with brushes, making them versatile for techniques like wet-on-wet blending.
When choosing brushes,, focus on ones labeled for that model or watercolor, synthetic bristles are durable and hold water well for those effects, get a mix of sizes like small rounds for precision and larger flats for washes. I tried storing mine haphazardly once and they dried out fast but then I switched to airtight containers and yeah, problem solved.
Look for sets with beginner tips included, or check YouTube for free guides. It's all about starting small and building up, you got this.