I faced it myself as well. I used 4 sturmpios supported by med truck and double LeiG. Used all my ammo for mines, since he would run into them at every point since the guy spammed his lmg rifle blob with 3 brain active brain cells it seemed.
If you face a good lmg blob spammer, go multiple sturmpios, try to vet them up and support them with med truck. Mine everything you can and get one or double LeiG. Then by the time you can, get stuka.
Can you explain how sturmpios work vs m1919?