Sorry, can't help there. Although I'm not entirely sure if I understand what you're asking properly, because pigeons certainly does support xmpp, in fact it's the only thing it really supports quite well as far as I'm aware. Its these other services that either don't use XMPP or don't use it (or any open standard protocol) any more.

We only use Pidgin for native XMPP intra-org chat via self-hosted, AD-integrated private servers, a role which it has served remarkably well up to our largest client site of about 300 users or so. For phones, we support Xabber or Conversations but all BYOD usage comes with mandatory wireguard wrapping. We don't have much occasion to experiment with Pidgin's multi-protocol functionality, as our clients typically have little incentive to facilitate and support internet-facing chat capabilities.