Here's my take:

The Dragon Castle's ability to have a dungeon nearby isn't a huge advantage on Jeb. Since you can't place dragons anywhere, even if you don't upgrade the Troglodytes. This means that all other Castles, when reaching level 7, become roughly comparable to it in this aspect. Upgrading them, however, is almost impossible without a significant loss of momentum.

If you can upgrade Angels from Conservatories, then I think the Castle is noticeably stronger. The main issue is money.

The Barbarian Castle is completely independent of the dungeon. It has 2 mega-units, creatures, and wolves + a bunch of goblins to counterattack. A couple of good defensive positions solve the problem of taking out the Hive. So, you get to the center earlier and have good upgrades. The Dungeon can only win due to its potential first-turn speed in battle.

Inferno vs. Dungeon – I don't know, based on Ignat's assessment, it should be at least as good, plus it has good attacking units at levels 3-7.

I think the Fortress is stronger, mainly because the birds can be placed on level 116 and have a large spawn rate. Strong units at levels 6-7 + a hero with logistics, which is very important for momentum.

Of course, you can get bad luck with any Castle, so you can't say that, for example, the Tower will always lose to the Swamp. But on average, I think it will turn out like this.