OAuth refresh token rate limit?

Let’s say I have a plugin that syncs watched status to Trakt for 1+ million users. That means millions of tokens needs to be refreshed daily to keep users authenticated. Would this be possible, or would I hit a rate limit/block on my app because of this?

Or do I have to contact Trakt as a developer to allow my app to do this and not get banned?

I’ve seen some discussions which hints that the Kodi/Emby/etc plugins that broke back in March got fixed, so I’d like to know how they’ve done it. Thanks!

Already posted on the api discussion, which is the better place for this.