Where I live, grape flavour is not common at all. The few times I tasted it, I didn't like it. It tasted super artificial and not like grape at all.
Buuuuut, when I was in Romania I ate some thick skinned, round, fleshy grapes that taste exactly like the candy grape flavour. They were good actually

I hate grape flavoring as well, and always have. Actual grapes? Delicious. Raisins? Also great. But candy pretending to be grape flavored just feels like a chemical approximation of the worst flavors in a grape.

Cherry is also shit. I love cherries, my ideal relationship is where I get the cherries from the milkshakes and give the pickles from whatever. But cherry flavored candy or soda or whatever, unless it’s a nice place and they’re just pouring maraschino juice in your drink, tastes like being 6 and being forced to drink cough syrup.

So I may only love it because it was my mom's favorite flavor so I have good memories of being a kid and picking grape stuff to share with her. But yeah I love the flavor. It's definitely one of the more divisive of the popular artificial flavors though.

I can't comment on it tasting like a soviet urinal, I'm not quite kinky enough to know how that tastes.

When I was a kid, I didn't like cherry flavour for similar reasons, but for some reason, as an adult my tastes changed and it's alright.

So I think grape flavour is generally just you, sorry to say. I certainly like it alright. :)

I wouldn't know I've never done enough psychedelics to experience synesthesia. And idk if I can, I suspect the I would go away before tasting colors starts from my experience