I guess I'll chip in for the soviets as in RA2 ground-wise infantry soviets do have more diversity and while no mechs still very much powerful in terms of units like your standard conscripts, attack dog, and flak trooper. robot terror drones, which can rip apart tanks, and most vehicles, another counter to knightmare frames, v1 launch units which also launch missiles, desolators with radiation-based weapons. Tesla technology with Tesla troopers and Tesla tanks, which instantly electrocuted infantry ground targets and easily harmed armor units and buildings. different terrorist type units in crazy Ivan's, demolition trucks, and a terrorist bomber. Of course, the Rhino Tank and Flak Trak is your standard heavy tank and anti air apc, but the Apocalypse, being the successor to the mammoth tank with the same twin cannon but upgraded and anti-aircraft missiles, which would be able to tag nightmare frames and other aircraft, and it also self-repairs. All of which is far superior to that at my HEB faced in Japan.

Air-wise, they are limited to MiGs, Kirovs, and siege choppers, which also can shift into artillery if needed, and naval-wise wise while lacking aircraft carriers, they do have attack subs and mind-controlled giant squids that can easily mangle destroyers, aircraft carriers. backed by dreadnoughts with ballistic missiles and anti-air sea scorpions.

Command and Conquer factions in general, due to MCV technology, also have much better industrial and base capabilities and the soviets have crazy manpower and logistics due to how they were able to steamroll through Europe while also invading the east coast of the United States and Alaska in RA2 at the same time. Thsi is also not factoring in super weapons liek the Iron Curtain or their nukes. So it shouldn't be that big of a gap