Even if it seems like “just adding a button,” changing languages would mean Airbnb must also ensure every translation is legally compliant, consistent, and acceptable for tax authorities in different countries.
In addition the Emiel's suggestion and Patricia's insights, I wanted to point out that as explained in this help article about managing receipts, they are generated in the language associated with your account settings. If you need receipts in a different language going forward, have you considered changing that setting perhaps?