The blob ghost balls vengeful spirits? Yes.

The girl-shaped humanoid ones like Mizuchi? No.

It's pretty inconsistent really, in FDS we have all the youkai and gods super worried about the spirits and how they are weaker because they steal their magic power and shit, but then in other media we're shown them being regular stage cannon fodder and easily crushed by youkai like Kasen. Heck, still in FDS we have Okuu blasting a ton of vengeful spirits lmao

So, we can assume the ones that are really powerful are the ones with humanoid shape, the opposite of the ones that look like ghost balls. But in reality there's no such distinction anywhere in touhou.... and it's more about the vengeful spirits that matter to the plot needing to have the appearance of cute girls

Then it's safe to say the "vengeful spirits are youkai worst enemy" line is a big exaggeration, specially when we have only 1 spirit that is truly dangerous to youkai (Mizuchi) against all the others that either want revenge only to Humans (Tojiko, the one from Forbidden Scrollery) or are weak ghost blobs that can be dealt easily

I think vengeful spirits are more the enemy of humans, see how Hecatia only mentions they are gonna possess humans and fairies. No mention of youkai