Honestly, my dream lemmy client would combine posts in my home and all feed based solely on the links in the post regardless of community or instance, and it would then provide UX to present the rest of the information if I choose to click into it.
Lemmy is designed around a concept that almost requires but definitely invites spamming links. Assuming you have good intentions and want to reach a wider federated audience, you would post your link to a few instances at once.