Covid has been global, lockdowns have been everywhere, UK is not unique and did not even have the worst of it in terms of lockdown strictness. While "averaged out" UK economy post-brexit/pre-covid might not look that much worse than EU, if you look into specifics the picture gets far uglier with entire economy sectors going bankrupt, all in all it was a spectacular self inflicted damage that will be felt for decades to come, especially now that US is becoming a hostile actor.