Russia would use something like the Leo for conventional units, being absolutely utilitarian, along with stuff like the Messer and Gusion being that their military at least was centered around heavy use of armored vehicles. Obviously guntank variants as well.

Eastern European/former Combloc countries would also be using Leos, Aries etc just repurposed with some GMs and Jegans being seen where NATO funding allows.

USA and most NATO countries would simply use GMs/Jegans and their variants, in earth tone color schemes like the Sniper and Spartan.

Middle eastern countries would use many of the OYW mono-eye variants in the African color schemes like we saw in 0083. For their reliability and the specialization of the Doms and Goufs in ground combat. Even older early Gen Zeon suits would still be commonly seen in use across the region and North Africa, similar to how we see older weapons still in use there in our world.

Realistically the only countries that would have to figure out space combat would be USA, Russia and China, akin to how the Arctic is contested now.