can water damaged sim cards be used in new phones

Unlikely, depending on what the SIM got dunked in.

Not sure I’d want sewage in a new iPhone, for instance.

But maybe just replace the SIM?

Some carriers can transfer the telephone number remotely, without requiring a SIM swap.

Others will send you a replacement at little or no cost.

You can just clean the sim card with a little IPA. Its not like your putting it in still sopping wet and with debris on it.

As long as its clean, and dry, there should be no issue trying it in the new iPhone.

Yes. The sim card will not affect the new iPhone if it does not work anymore. It will simply not be detected by the iPhone.

As long as the sim card still works, it should fine yes. If its actually damaged, then it won't work, and you will need a new one.

You write that like believe that various folks would ever clean off a sewage-dunked SIM and re-use it.

More than a few of us will “Nope” right out of the whole refresh-and-reuse discussion.