1. By default, I'd priotize opening that page in a native app the user already has or a web-based app he has some link with (zapped it, known app in his network, etc etc...)
2. By selecting who you are first, the app adapts the Verifiers it shows to your npub
3. I'm including Verifiers in my onboarding flow so that an onboarded user has an initial set of Verifiers (preferably independent from the app) like he would have initial Relays, Blossom servers or Mints.