The Caucasus front in Barbarossa will be... interesting.
Interesting yes, but I dout it will have a great overall impact. I suspect it will be a major resource drain for Germany.
A Caucasus Front can have two options:a) the Turks pulling most of the weight with minimal german participation, or b) major german participation with secondary turkish one.
Turkey in TTL is saddled with much debt, while having lost a great part of the pre-war GDP and most of the export-producing regions. In OTL, Turkey with a much larger economy didn't have enough rifles and light equipment for all the reserves, despite the heavy focus on re-armament. Moreover, in TTL Turkey starts with less military equipment as they have lost dozens of artillery pieces to Greeks during the last war while they haven't captured the equipment of 2 greek corps as in OTL. They have also received less equipment from Italy, France and the USSR as the war ended earlier, France never gave any equipment and Italian distanced themselves during the last few months. To quote our author on previous mentions of turkish supplies:
- 48,000 Mauser rifles and 20 Skoda 75mm guns that in OTL the French returned to the Turks, were in TTL sold to Greece
Moreover, Turkey will lack at least a significant part of the OTL Soviet assistance:
- 39,000 rifles
- 327 machine guns
- 54 artillery pieces
I am also under the impression that France provided Kemal with 1,500 light machine guns. We have also discussed the riddle of the OTL italian assistance that was surely more than 20,000 rifles.
Suffice to say that TTL Turkey cannot afford to equip its army. Therefore, if Turkey was to undertake a Caucasus Front and secondary ones in Syria and Iraq, Germany needs to provide equipment for ~42 infantry divisions.
The other problem that applies to both turkish and german participation in the Caucasus Front, is what else? Logistics.
I believe that the Turks will build the otl line towards Erzurum and Kars. Therefore, the whole front will need to be supplied by just one single-tracked rail line. How many divisions can someone supply with this single line? 10? 12? 15? All the supplies need to be sent via the greek and bulgarian networks to Constantinople, then move them via barges to the asiatic side and load them in trains. In TTL Turkey has much less capital to invest in the railways during the Interwar and I suspect that the Greeks have kept the locomotives and cars they captured in the war (that were the vast majority of the existing rolling stock). So, the turkish railways will receive even less investment compared to OTL. If the Germans want their front, then they will have to dedicate
a lot of resources just to make the sparse turkish rail network semi-decent and operational.
Overall, it seems to me that a Caucasus Front will be a huge drain of resources. But what about the results? There won't be armored corps dashing through the steppes. There will be infantry divisions fighting through >2,000m high mountains just to pass through Kars. In that terrain, a single soviet corps can stop a turko-german field army. The local Armenians, 21 years after the Genocide, will fight tooth and nail in Kars Oblast.
And then ... here comes SOE dropped in kurdish regions armed with gold sovereigns and promises (as the author have stated in a couple other occasions).
My guess is that this will be the result of an Axis Turkey: Sevres Kurdistan and a Soviet "Wilsonian" Armenia, with an enlarged Soviet Georgia getting Lazistan.