There are a huge number of app based solutions. Enterprises are against them because they can't expect their employees to install 20 different apps for 20 different vendors + the cost of reviewing and onboarding them.
So you either need to support SMS or several of the major 2FA app providers including the crappier implementations like Microsoft authenticator.
So you either need to support SMS or several of the major 2FA app providers including the crappier implementations like Microsoft authenticator.