While I do like that they tried to address the lack of possibility for players of different levels to help each other or play together in Eureka, something that has had a LOT of complaints about it since then (and rightly so), I do feel that the fix to the problem comes into a content that literally doesn't need it or actually makes use of it.
1) CEs and fates work like in Bozja and totally ignore said knowledge level, ensuring that everybody can participate no matter if they're fresh into the content or if they have mastered every phantom job, are lvl20 and are kited out in +2 gear. Whether this is a good or bad things is another story, but this on its own makes level sync totally irrelevant for that specific content.
2) Knowledge level sync is only applicable for mob farming (also referred as gold farming in OC). While it is very potent to level up phantom jobs, most people will only make parties to farm mobs at lvl 20 either to farm gold coins and/or level their phantom jobs, because that's where rewards are actually hefty. Full lvl 20 parties also don't need nor benefit from the level sync. Most if not all players just level their knowledge level as they go by doing CEs and fates in the fate train otherwise, where sync is irrelevant.
3) The relic step specifically requires items that drop from CEs and fates, and not from mobs, therefore funneling even more all the players getting into the content toward CEs and fates, and not mob farming, which again, makes sync irrelevant in their case.
4) The only fringe case I can think of is when players feel like helping lower levels to do their challenge logs for the week, where I think that yes, sync suddenly becomes applicable and relevant.
So while I think it's a good thing this was introduced into Field Operations, ultimately I think Occult Crescent does almost everything to make it totally irrelevant anyway, but perhaps there are cases I haven't seen or thought about?