The Switch 1 is almost 10 years old. Batteries don't have that much longevity.
And it was unnecessarily hard (actually dangerous due to fire risk) to replace it with a 3rd-party battery replacement due to excessive amounts of strong adhesive holding the battery in place.
My launch Switch 1 battery is still working. Capacity is probably 80% or less but it still works fine.
My 8 year old switch is happy.
The switch doesn't fast charge at absurd rates and generally has good thermals.