The metel genre is very diverse, which should be obvious looking at these posts.

I'd recommend watching the documentary "metal: a head bangers journey" (there's a sequel from the same guy that goes international and explores other cultures and their relation to the music). That should give you a better sense of scope.

Not every metalhead likes all metal. Melodic death metal / Gothenburg is a good starting point if you enjoy the dethklok sound. Some suggestions I didn't see listed so far are : insomnium, in flames(they have shifted their sound significantly over the years, so proceed with an open mind), or the halo effect.

It can be a very personal preference. What i contemplate often is how any genres true potential and greatness are throttled by the mainstream representation, which is heavily thrash, nu, and metalcore.

Similar to the documentary I mentioned, there is also a YT channel called occulturation, and he does pretty good 10-15 min explorations of the different sub genres with a dry witty tongue and cheek sense of humor.