The correct move here is not to try and plead with the EU or do other things which implicitly recognise their authority to make such regulation. The correct move here is to hold such regulations in contempt and expressly refute any claim the EU makes to regulating web browsers as illegitimate.

I may as well add that web browsers are generally open source software and their source code thus a form of speech. Recent actions by the EU have made it clear they are trying to start to exert control over web browsers, which they presumably see as prime estate for exerting control over the internet. The correct answer to this is to distribute web browsers from jurisdictions with strong freedom of speech (code) protections, remove any assets from the EU which the EU might try to take hostage to extort compliance, and respond to the EU's frequent attempts to assert "if anyone in the EU uses your product, you have to comply with our rules" with "you and what army."