Not at all, look at the linked map. We've only one party in ultimate control which flicks between the big two but we don't have only 2 parties with any viable chance at politics at all. The SNP etc, despite having no executive power, still manage to influence political thought. The same can't really be said for the USA in any meaningful way.

https://en.m.wikipedia.org/wiki/2024_United_Kingdom_general_election#/media/File:2024_United_Kingdom_general_election_-_Result.svg