LOG, I just don´t see the investment (mainly the 2-3 techs plus changing templates) as worthwhile, even less so with MAINT. I´d much rather get a Decryption bonus, thank you very much. IMO the issue isn´t so much supply as proper planning bonuses and actually getting your guys trained, equipped and in position. That way you can do with less, however multiplayer is at times quite chaotic so just grabbing that stack of divs and sending it to the front without too much attention to detail happens.
Also, you had the port of Athens for incoming supply there ... I think he tried pushing 30+ divs south from Albania and Bulgaria through the mountains, with the Bulgarians clogging up the battle lines as well and the Yugos trashing any hope for quick German help.
In an area where he had little depth, a potential enemy in his back and 4 air zones to cover. Hehe.
Hell the Brits even tried to reinforce mainland Greece historically:
About 58,000 men and their equipment were moved to Greece by 2 April. These comprised the British 1st Armoured Brigade, the 2nd New Zealand Division and the 6th Australian Division, followed https://en.wikipedia.org/wiki/Operation_Lustre
by the 7th Australian Division and the Polish Independent Carpathian Rifle Brigade.
Two infantry and two armored divisions were in place on the Aliakmon Line, south-west of Thessaloniki (Salonica), before the Axis (German, Italian and Bulgarian) invasion (Operation Brevity) on 6 April. The Greek Army did not retire to the Aliakmon Line as expected for fear of being overrun by the more mobile German troops during a retirement and the Allied troops were left vulnerable. These forces had little effect on the German invasion and they were evacuated (Operation Demon) on and after 24 April.
so maybe have some plan for that. The original Italians finally sent in the Regia Marina and got a good licking at Cape Matapan, also smth to work for as ITA (Convoy Raid in the Eastern Med to cover your invasion against the aliies convoying in troops), or maybe do some landing yourself.
But then Italy ran Novus Imperium Romanum instead of just joining the Axis, it all seemed a bit random.
At least we had a basic plan (KRUSH RUSSIAH!!!) last time and some coordination. They did good on the World Tension though, but undid themselves on the Balkans, and quickly.