Battery replacement for 2019 Retina 13" MacBook Air

Under those circumstances, the only aftermarket vendor I could comfortably recommend is OWC / MacSales. Their website will properly identify the battery you need: https://eshop.macsales.com/item/NewerTech/BAP13MBAR55K/

Be sure to read the footnote. That battery is not easily replaced. When Apple does it, they replace the entire bottom case. Of course I understand that's not an option for you, but you might want to research Apple Authorized Service providers. They may have more flexibility.

"Ships: Pending" is not encouraging either. You may be in for a long wait.

Mac Repair - Official Apple Support

Don't replace it yourself.

Battery sellers ID batteries by model, year and etc so you have to know the data. Those details positively ID the correct battery for your unit.

But .... have Apple do it.

You ID your battery with the details of your machine: 2016 MacBook Pro 13" Retina non touch 256GB disk 8GB RAM. Disk size and RAM may not be needed, but you need to have all the details of your Mac available.

Did Apple say they would replace the battery if you allowed them to "fix" the water damage? The real problem is the water damage; a new battery is not going to reverse the corrosion. Keep in mind, Apple doesn't really repair much at all; replacements are the rule.

If your Mac is this damaged, you need to consider a new, or newer, one.

I'm outta here ... no need for my redundancy.