I don’t think this is correct. EU is pretty strong in favour of data localisation, UK is not. Moving customers to California doesn’t mean they are no longer under UK privacy rules, which of course are identical to EU privacy rules (for the foreseeable future, could change of course).
Common in the US, but viewed as bad corporate governance elsewhere. A separation of the roles has been a recommendation in the UK Corporate Governance Code since 1992, for instance.
https://www.legislation.gov.uk/uksi/2019/419/made