Hi, I've been looking at some transatlantic itineraries from flights.google.com that have LH and LX flights (e.g. ZNY–ZRH/FRA–MRS) on LH or LX the whole way. I can click on the "buy with United" and the flights are there on the united.com payment page though not with UA codes. When I search united.com — it will only give me the legs ZNY–ZRH/FRA legs on UA metal. Any reason to avoid these flights as I would rather fly LX/LH? Also, would these flights be covered under the UA flexible booking policy if purchased from united.com even if they don't have UA codes??

Thank you thank you!