Unless they're forced to do so by the EU, I'm going to guess that Apple won't want to lose out on selling devices in the EU or whatever punishment they get because of a port. Whether it will be voted in or not, is another matter, but it's a proposed piece of legislation which will be voted on in 2022 I believe. Whether this will force Apples hand in other accessories, such as the APM is another thing, as I believe it's just for Mobile Phones at the moment.
The proposal is broad and includes headphones, but it is currently at proposal stage and isn't on any agenda for 2022, it may still get a vote in 2022 but quite unlikely given that it's only been revised once. These things usually get revised multiple times. Assuming it passes (which isn't a sure thing), it will definitely get contested in courts and the legal process would still take at least a couple of years. Assuming it goes through all of that and still comes with its fundamentals intact, the proposal itself has a long transition period (minimum of 2 years, and up to 5 years in certain conditions), and then there are grace periods that could last years as well.
As in, don't expect this to make any difference before 2025 at the earliest, more likely 2027 or 2028.