That may sound weird to you, but my favorite devices are those that grew on me and became special.
Like the Nokia N900, my first Gameboy or my favorite X24/X60 thinkpads. They have served for years and have a place in my heart.
My steam deck became special too as it took this type of special place.
I will not abandon the poor thing to the siren of a lightly upgraded hardware.
We have still great gaming times to live.
I’d say as long as your current deck works fine you don’t need the mid gen upgrade. But if you you feel you’ll benefit from the better battery maybe consider