Re: Brexit
Re: "I'd say that for most people data charges when roaming are much more of an issue"
The use of data is also covered in the "Roam-like-at-home", although your operator can specify a cap - just as many specify a tethering usage cap.
See https://ec.europa.eu/digital-single-market/en/faq/frequently-asked-questions-roam-home for details.