I was viewing thunderstore, and noticed that they had a really neat feature for sharing modpacks. They use a unique code that people can use to import modpacks of varying sizes>
Perhaps the new Nexus APP can use a similar system? Free Users can use a code to share a small modpack (up to 50 Mods), While people with subscriptions can share larger packs (Up to 100?) and people who want larger mod collections use collections themselves?
Could be something to look into perhaps?