you are likely worried about nothing

how do you expect a dock to mess up the power/battery?

get an official dock and it comes with an original power supply. It’s a bit more $$ than alternatives, but it would be the ‘safest’ solution.

also, the battery is a fairly easy replacement, if needed. But likely it won’t be needed

First and foremost, the Steam Deck uses USB-C PD (USBC Power Delivery).

This is a standard between the wall adapter, cables, and hardware requiring the power (i.e., Steam Deck).

You could use a 10000000 Watt capable adapter, but through negotiation the Steam Deck will only ever ask for 45 Watts maximum. I personally have a 100 Watt capable adapter and can verify both on the Steam Deck and with a passthru digital meter that tells me what is being drawn.

So to simply answer your question - literally any Dock, so long as it touts having USB-C PD.