Deciding whether a better grinder matters more than replacing a basic brewer

I have a basic pour-over cone and a cheap grinder that produces a mix of powder and chunky bits. The temptation is to buy a fancy brewer because it looks like the exciting upgrade, but uneven grinding seems a more plausible cause of the bitterness I keep tasting. If you had one modest upgrade budget, would you prioritize a more consistent grinder and keep the plastic dripper? I'd rather make better coffee than acquire another beautiful object.