I just played a Co-op game with a (very new player) friend as the Axis. I was on Germany, he was on Italy. He had never won a game of HoI4 before. He has watched a lot of guides on youtube, but by no means is he a skilled Italy who knows all the tricks. He justified on Yugo right before finishing War With Greece, and tension went up to 27% about a month before he declared on both in January 38. Despite the tension increase, there were no new guarantees, just the standard Romanian guarantee on Greece. On historical AI it seems that France does its Buy Time focus in early 37, and the game is pretty lenient on the window an Italy player has to annex the Balkans.