No Face ID issues thus far, but I can say third party app issues are to be expected. If there is a public beta track for their app there is a chance the developer will address those issues with a beta release. If not, you will have to wait for Apple to refine iOS 26 to the point the dependent behavior is resolved, Apple current released version of Xcode allows iOS 26 fixes, or for the GM release.
At this point I am experiencing some annoying CarPlay iMessage reply inconsistencies while music or a third party podcast app is playing.
The whole green bubble/blue bubble stuff was such a contrived story to begin with. iMessage is only popular in the US and Apple's RCS integration was pushed by the Chinese government who want their carriers to support it.