We built a house seven years ago and installed Cat 6 shielded cable throughout for phone, internet, and TV over internet. It was a big EMF improvement from a previous home where DSL came over regular phone cables.
Shielded Cat 7 cable is now available for high speed fiber internet that may be what you are looking for:
https://www.amazon.com/Ethernet-Internet-Network-Shielded-Switch/dp/B08LK8HNQ3/ref=sr_1_20?sr=8-20&xpid=iQo_YTu_XIUwY - that link might not work in the UK.
Best wishes!
Bonnie