I ran the tests 6 months ago in identical layouts in HD and DE. Details can be found in comments in https://www.reddit.com/r/aoe2/comments/gk3ljr/whats_up_with_gunpowder_units_in_de/fqoxq36/?context=3
TEST RESULTS OF HAND CANNONS VS CONDOS: HD 3039/10000 missed. DE 1577/5000 missed
HD 69,61% accuracy vs DE 68,46% accuracy = within margin of error.
TEST RESULTS OF CONQS (10k sample in each 4 tests):
HD vs condos, DE vs condos, HD vs vils: 72,6-73,0% accuracy at 5,8 range
but here is the proken part DE vs vils: 67,86% accuracy.
Even missed shots can land a hit if the randomized trajectory happens to land on enemy hitbox. (there is also a SOTL video about this topic.
Now since the base accuracy is 65%, if we reduce that, HD conqs hit 8% of missed shots due to larger vil hitbox but DE conqs hit only 2,8% of missed shots. That would mean vil hitbox is reduced to about 3/8, so a reduction of 62,5%.
Obviously this would hurt only conqs since nobody raids eco with hand cannoneers.
Another “bug” seems to be that gunpowder pellets vanish faster in DE. At one point during the ongoing 2v2 tournament, there was a dozen conqs chasing vils and taking shots at their backs, but villager valking at a brisk pace could not be hit. Pellets vanished too early. This one afaik is not only specific to villagers.
IMO, fixing these two changes would already be enough to fix the Spanish.