It reminds me of the "Crown" map. It had packs of units on the "Crown" peninsula, a labyrinth with a horde of minotaurs, and even a Vampire Lord in one of the dungeons.
This masterpiece is available on this wonderful website along with other amazing maps. I recommend trying them all.
https://heroes.ag.ru/maps/top

I found something similar, maybe even more challenging :))
Especially when playing on Champion difficulty, I got stuck here – a neutral army of 735 Black Dragons, which are also growing, and a level 40 Ranger hero with 5 Chaos and Order magic, 100% resistance, 100 defense, and 23 speed – and also with scouting, what a pain, he's even hidden, you can't sneak past him :(
The name is "Seven Steps to Glory," I think.
He has an Armageddon spell that deals 600 damage :)))

Added 4 minutes ago
And it's all because they are divided into 6 stacks – and while I was heading towards them, they grew much faster than a single stack :(

Added 11 hours 52 minutes ago
It's funny, I killed the hero, but I still can't pass with stealth – that is, he continues to provide scouting with his "coffin" – isn't that stupid?