The Five-Eyes agreement allows the UK and US to share any intelligence material immediately. This is 100% orchestrated with American intelligence agencies to allow them to get American data.
When push comes to shove, the US government will probably side with the UK.
Although I agree — and also left the UK in part* because this law was clearly going to blow up like this — I would add that the US and China are about equal now, so look at what gets done to Chinese tech firms that don't play nice.
* the other part being Brexit, whose saga still isn't over given the Reform party opinion poll rating and them wanting to also leave the European Convention on Human Rights which has bad things to say about government surveillance
