> What do I need to do to make a difference, and how much time will this take?
EU or US?
> what's the path? Legislation?
Send them a letter explaining why this is bad for you. Keep it strictly factual and ideally concise. Copy Google’s legal [1] and any relevant digital or markets regulators. (If in the US, don’t forget your state regulators.)
Wait two weeks and then call the elected. Make sure they’re aware, and talk through your options. Send a letter thanking them for the call, incorporating any new information and actions they said they would take, and copy all of the previous parties again.
More work: reach out to other top developers and organise an open letter. This will be hard because everyone wants to include their pet issue and everyone will fight over scope and language.