FWIW, I work for a major financial organization in the UK as a software architect and I've brought it up more than once over the years in various roles: not a single bank in the UK supports Yubikeys or custom Authenticator apps.
Not one (I last checked about a month ago!)
Security, while pretty good, is still lacking imo!
I thought they still did for website flow at least. Bizarrely we seem to think that phone apps are infinitely secure and don't need the extra step because biometrics?
Isn’t it because the assumption is that a mobile device is personal in 99,99999% of cases while it’s common (less now than 15 years ago) with shared computers in libraries, schools, etc.
Not one (I last checked about a month ago!)
Security, while pretty good, is still lacking imo!