As long as they're not region locked, you should hopefully be able to import them if nothing else. I'd absolutely pay some extra import costs to be able to easily swap out my battery.

In most cases, when the EU passes a law to make something happen, it's cheaper for manufacturers to make that EU-compliant device available worldwide rather than make a specific version just for the EU market. So, I'd expect user-replaceable batteries in flagship smartphones to be available in the US by 2027 also.

I'm hoping that, similar to USB-C, this just forces Apple to make the iPhone better.

It will most likely come at the cost of water resistance and thicker phones.

Most likely will, since manufacturers won't want to design multiple models with and without replaceable batteries for the most part.

Not that I'm aware of, but I've lost 0 phones to water and many phones to failing batteries, so I'll take that trade.

The 2014 Samsung Galaxy S5 had a removable battery and IP67 rating.

All recent Galaxy Xcover phones have both an IP rating and removable batteries.

I have Samsungs Xcover 5. It is IP68, and very user servicable. Toolless battery replacement.