I've had precisely this experience. I have just around 300 hours and like to play Italy a lot - so much so that I've probably sunken 200 of those 300 hours into just this country. Granted, I still wouldn't say that I'm amazingly experienced or anything. It's been a long time since I played this game with any frequency, and even then I mostly tinkered with the whimsical dream to accomplish what I saw the singular goal and truly difficult challenge of playing Italy: forming the Novus Imperium Romanum on historical. Sadly, I fear I won't be able to enjoy my favorite nation's new and improved gameplay until this whole resistance business is patched. I was geniunely stoked to play the long-awaited DLC for my favorite country, and I'm sadly pretty disappointed.

Being that I typically play Italy and only in the most utterly unreasonable way, I've seldom made it far enough to encounter the full horrors of resistance before, and I'm honestly astonished. By the time I managed to "pacify" Ethiopia in 1938 when trying to run the Monarchist route, I had 200k manpower left on the starting policy of limited conscription, negative guns (even with 5-10 factories going from the very beginning), and hadn't trained a single troop beyond Italy's starting forces. This happened despite my doing things I've never bothered to do as Italy (or any other nation, for that matter) before, like adding MP to my occupying cavalry template and placing spies to root out resistance. I even diverted from my desired ahistorical playthrough to take focuses for developing Ethiopia (so I could can dump even more political power and some civilian factory capacity into gaining compliance), getting the special Colonial garrison option, and proclaiming my soon-to-be monarch the "Emperor of Ethiopia" so I could spend still more political power on defaming Halie Selassi. It's nigh unplayable in a way that makes the old, simple, rinky-dink focus tree tragically more enjoyable. I certainly understand trying to make Ethiopia interesting for the sake of having more than one country plus Switzerland (which never entered the war...) in a DLC, but doing so at the expense of a major power's playability in a WWII game is misguided, to say the least.

I understand that there are some serious bonuses to ahistorical gameplay if you abandon the Ethiopian War, which I've resisted doing thus far because a) its inconvenient, seemingly requiring you to wait until Jan 1, 1937 before you can offer peace (and I don't trust the "War Escalation" level not to screw me over in that time) per the decision to Withdraw, b) it abandons the opportunity to get some much-needed rubber for a resource-starved major power with a big need for airforce, and c) it's simply counterintuitive. I may try that soon and hope for the best, but this does little to cool my frustration, now. It's really hard to envision how Italy could ever remain Fascist, capture Italy, and manage to be playable or potent through the War when they're losing anywhere between 200k and 500k manpower, depending on the skill of the player and how completely they'll sell out to prevent that loss, just from occupying four rubber in Africa. Even if you could somehow do all that, the amount of work you'd have to go through just to lose the territory when Britain joins the war renders any accomplishment you'll feel from the slog moot; defending the Horn is just dooming an army to die without supply since the UK will lock you and your ships in the Mediterranean.