Is it a bit boring? No, actually, all the musical elements there are very interesting.

It seems you haven't heard of progressive metal; it's interesting in itself, although some bands do have interesting elements, like Children of Bodom (by the way, it's not just melodic; you can also hear power metal, neoclassical metal, and thrash metal in their music; I would classify them more as technical death metal), but still, it's not that interesting...

More interesting bands: Netherbird (Melodic Black Death Metal, but they focus more on atmosphere), Cynic (Technical Death/Death-Jazz (cyber) - a very atmospheric band that plays very well), Textures (Math Metal/Technical Death - they definitely have some elements of it), Hypocrisy (since they started playing melodic), Engel ((Melodic Death/Metalcore - I like them)).

But I can't understand the statement that death metal bands don't know rhythm, no matter what. Explain.

Well, the rhythm is specific; it sometimes gets lost due to the speed of the performance, and for example, CRYPTOPSY - Worship Your Demons, this composition makes you sleepy, for example, although for some, it's a standard...

But you probably won't understand anyway))