I don't have good news. Dell doesn't carry batteries for a system more than a few years old. I checked there and they don't show any batteries available. The next place to check is Parts-People, but I checked and they don't have any in stock for your model. You could contact them to ask if they will restock. Otherwise, you would have to buy a battery from elsewhere. It will not be a Dell battery. It might work, or it might not, or it might fail before long. If you buy such a battery, make sure to choose a vendor that has a good return/refund policy.
I bought my XPS 13 9370 back in 2017
"DS: My system is out of warranty but I need to replace my battery."