N1b Tha
N1b YubiKeys don't support firmware updates, so you're stuck with whatever firmware (and bugs/exploits) the device shipped with.
There are a lot of rasons why I don't want to use a Yubikey. This is one more. But I did want to keep my answer short. There are a lot of pages that compares the different keys. I think we don't need one more.
N1b Regarding OP it looks like you're out of luck as currently OnlyKeys won't work for your use case
Bad luck. But is it possible to use it at simple 2fa?
N1b You could create a user profile with Sandboxed Play Services exclusively for the apps and websites you use with your OnlyKey, but I guess it's not a good solution for you
You are totally right about that. It's no option for me.