Only way to progress is to grind it out. The devs assume that 3 months into release is enough for people to grind tanks to a decent level with some decent emblems to make do with this event. Invasions gives a lot of pumpkins according to lieutenant level, me being 46 gives about 456 pumpkins per invasion tile. Poc also gives pumpkins scaling with stage difficulty. Levels for event reset per day.
FYI near end of third tile for my tanks who are around lvl 25-35 is where I start to struggle where as in PoC i can clear up to stage 31 (level 62) so that in itself speaks for difficulty curve.