They just come out with gun rack for pre-order.

https://cfmotousaparts.com/product/flexgrip-pair-fits-all-cfmoto-cfconnect-holes-use-for-gun-mount-shovels-rakes-cfmoto-oem-852114-00001-preorder-begins-shipping-late-fall-2021/?mc_cid=aa5b75a55d&mc_eid=d621303613

I use this $20 https://www.cabelas.com/shop/en/plano-sportsmans-tote cargo box on mine and it works great. I use some 550 cord and loop it under the cargo rack from the tie downs on the box and it's pretty solid. I ran all fall with it and it never fell off the quad.

You could also add a rack extender and buy standard rail mount accessories for it.
https://cfmotousaparts.com/product/rack-extender-rear-c600-cfmoto-oem-9ds-802200-6000/
https://cfmotousaparts.com/product/rack-extender-front-c600-cfmoto-oem-9ds-802100-6000/

[We finally have some accessories available in the US now!]

We finally have some accessories available in the US now!  

https://cfmotousaparts.com/product-category/new-accessories/?orderby=price

I would think this Can-Am mounting system (LinQ Replacement Part 715001707) would work. It looks very similar to the one CFMOTO uses. And there are adapters available for the LinQ mounts.
https://can-am.brp.com/off-road/us/en/shop/accessories-shop-by-usage-atv/linq_system_accessor/linq-replacement-part.html
https://can-am.brp.com/off-road/us/en/shop/accessories-shop-by-usage-atv/linq_system_accessor/linq-base.html

Just a FYI, the posts on the linq mounts are about 1/2" to short to work on the 600 rack.

I use recreational fuel which doesn't have the ethanol in it. It's about a $1 more a gallon where I live, but totally worth it.

I did find these quick release assemblies for the cargo racks, but they are only available in Australia for some reason.
https://shop.cfmoto.com.au/5hy0-809100-quick-release-assy

I would think this Can-Am mounting system (LinQ Replacement Part 715001707) would work. It looks very similar to the one CFMOTO uses. And there are adapters available for the LinQ mounts.
https://can-am.brp.com/off-road/us/en/shop/accessories-shop-by-usage-atv/linq_system_accessor/linq-replacement-part.html
https://can-am.brp.com/off-road/us/en/shop/accessories-shop-by-usage-atv/linq_system_accessor/linq-base.html

Has anyone tried the Can-Am LinQ Replacement Part 715001707? The mount hole looks similar in size and if it fits could be used to mount a cargo box or rack. https://can-am.brp.com/off-road/us/en/shop/accessories-shop-by-usage-atv/linq_system_accessor/linq-replacement-part.html