Since all we're in an "counting chickens before they hatch" mood, here's a revision. Our infantry still don't have an AT weapon. To hold the mountains outside our capital, lighter vehicles are going to be key. (See how our Sarukh rocket artillery has evolved role-wise into a pack artillery mountain gun.) If we hold the desert but lose the mountains, street fighting in our capital is going to choke heavier vehicles as well.
The Canners put out a modern ATGM system, but it hasn't been getting much love because it's too immobile hunt and then evade targets.
So...
UF-RPGM-46 Ribeye Recoiless Rifle Motorcycle Sidecar
The classic AS-M17A motorcycle sidecar has been stripped of its MG and passenger. It its place, a single 1 1.5 meter long recoiless rifle launcher and two several additional rocket shell reloads for roughly the same weight. The launcher is on a short tripod that can be aimed, fired, and reloaded from the motorcycle seat with some leaning and reaching. The Ribeye is a 155 90 mm diameter projectile with a 6 3 kg HEAT warhead. The Ribeye is designed to ambush modern MBT's, namely the M4A1 Bull, from any aspect for a first shot kill. The launcher includes a Eagle Sight style 4x optical scope. What appears to be a bayonet lug has been hastily sketched onto the design document.
It's unconventional, but dirt cheap, tank destroyer that can be fielded in any terrain as well as being air dropped by Trustfall parachutes. Tech-wise, I'm trying to go for an M67 recoilless rifle, but with a longer tube for better range.