I’ve found that the ergonomics of Deck really help to make it feel lighter than it actually is. I’ve happily held mine for ~45 minutes at a time with my elbows resting on my chair arms. As another commenter mentioned, it’s worth keeping an eye on your posture (I’m definitely really bad with this - leaning over playing my Switch, Deck or reading a book)!

I think the main limiting factor here is battery life. But nowadays I’m never that far from a plug point or battery bank to be fair.