I was going to suggest this too. According to the Android dev site "Google Play Billing can be used to sell the following types of in-app products: One-time products: An in-app product requiring a single, non-recurring charge to the user's form of payment. Additional game levels, premium loot boxes, and media files are examples of one-time products."[0] So could you have buttons to buy a "bronze supporter badge", "silver supporter badge" etc. (trying to avoid using the word donation in case it triggers something), perhaps even enabling a "Show my supporter badges" page that shows the ones you've purchased? Kind-of unnecessary extra dev, and as you say Google will take their hefty cut, but might be better than nothing.

[0] https://developer.android.com/google/play/billing/billing_ov...