It looks like the developer may be in the EU. If they offer the add-on as a business, it may be worth looking at if any of the internet rights legal groups will help take the case up under the 2019 EU platform rules.

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32...

These make various requirements around how Google act, and include requirements around removing products from platforms.

As an aside, it seems crazy that we allow platforms to take action when in positions of such clear conflict of interest, but that seems to be the way of the tech sector.