The weapon emblems for earning a rank is a very nice but extremely elementary way to reward players for the ranks they earn.
Players want to be able to show off their achievements. For some reason you don’t have any cosmetic awards for game achievements or beating campaign. At least you got ranked multiplayer right, but it needs to be expanded. Getting diamond in season 1 is way too easy (as evidenced by this bell curve https://www.halowaypoint.com/news/halo-infinite-playlist-challenge-update) and as such, the diamond reward is less rare/cool than it should be. This problem would be fixed by adding another reward for future seasons.
Also, possibly add rewards for different tiers of onyx. Onyx 1500, 1750, 2000 perhaps?
Adding a “top 500 rank“ would also be a good way to divide up the top rank and is an industry standard for a reason.