Some authenticator apps (i.e. Microsoft Authenticator) supports some non-standard uri query values for extra informations, such as image (which used to set the URL for display logo image), and so on.
Could you please consider to add an ExtraQueryValues dictionary into the OtpUri class and use it to append any extra url query values when invoking the ToUrl method? Although it can be done by manually update the generated string using 3rd string URI handling methods, it will be much better if this feature is integrated.
Many thanks!