Battery life definitely depends on what you are playing. In BG3 I get around 2 ish hours. But I can play older games like Morrowind, or newer retro style games like Skald against the black priory (10/10, do recommend) for 6-8 hours, maybe more.

You also have a lot of control to improve battery life like clock speed, frame rate limiting, etc.

But yeah it has a huge screen and if you play newer games with good 3d graphics it drains fast. Switch doesn’t really have those kinds of games so it’s not a 1:1 comparison.