Aw, that's a bummer. First Vanguard and now AWS support only Yubikey brand U2F devices. I wonder why that's happening?
Hopefully this practice remains limited. I really don't want haul a bag of different security keys around with me to access all of my services.
The link to "see information about supported configurations" is 404: https://docs.aws.amazon.com/iam/mfa-u2f-config