You might like some of Haken’s heavier stuff. They’re primarily prog but they go hard, too.
Try the album Vector and the album Virus.

From Virus i recommend you try the song Prosthetic
and the song Messiah complex V: Ectobius Rex
From Vector I recommend you try the song Puzzle Box
and the song Veil

Their new album Fauna is really good and has a good mix of different styles which includes heavy elements as well.

Come back if you like them I will recommend more!

🤘 Haken! 🤘

It’s also okay if you don’t like prog, i recognize it’s too different for some. lol

Give a listen to Testament! IMO the music is thrash so heavy it borders death metal, and the singer ventures into growling only occasionally. My gateway drug into Testament was their Titans of Creation album.

Just to be clear; are you wanting heavy metal music that’s only instrumental? Or are you wanting heavy metal music where the vocalist doesn’t sound like a small angry demon with a cold that just got karate chopped in the throat?

I forget which one, but one of the Between the buried and me albums has an instrumental release. Honestly, all of their albums I recommend regardless because the musicianship is excellent.

Scale the summit is more along the lines of prog metal but purely instrumental (I think).

Protest the hero is prog metal that has a near minimal amount of death growl (still some).

Animals as leaders which has been mentioned by several people.

Exivious is decent, I’m like 90percent sure they’re instrumental.

There’s a Japanese band called té, which is way more prog rock but you might like that.

Death, despite being one of the progenitors of death metal, is less intense on the death metal growl vocals. To me, early death metal in general is a bit different sounding than modern death metal. Regardless, Death has a pure instrumental song called Voice of the soul which is part acoustic. It’s probably one of the most acoustically beautiful songs written in the genre.

For instrumental music with no vocals, try: Wide Eyes, Invent Animate (their instrumental versions), Modern Day Babylon, I Built the Sky. These aren’t quite Death Metal, but they have really complex guitar and drum pieces.

For with vocals: Sea in the Sky, Ignea, Unleash The Archers, Corelia (also has instrumental version of their 1 album)

Anthrax
Haven’t listened to them much in years but I used to like their album, The Sound of White Noise. Singer can be a bit gruff but doesn’t quite scream like I think you are talking about.

Try out the band called Scale the Summit

Elder

Dvne

Bossk

Keygen Church

Julie Christmas

Cult of Luna

Sgàile

Nightwish

Skiltron

Glorryhammer

Creeper

No real death in that list though - the vocals are part of the genre

So you just want instrumental? Check out Buckethead.

Maybe try symphonic metal. Bands like nightwish, within temptation maybe?

Hm, Animals as leaders? But it’s not very thrashy.

You might like a lot of stuff by The Sword.

Example

There are vocals but they are smooth and crisp rather than the xtreme death metal habit of trying to eat the mic.

It probably wouldn’t fit your thrash and death metal tastes, but sludge metal and doom metal are a lot less likely to have screaming or annoying vocals in them. I personally really don’t like screaming even though I like metal, haha.

Otherwise, acoustic metal is where you want to land. It can be hard to find in my experience, though.

I am also not a fan of super growly vocals. There’s a lot of stuff I love musically but the vocals put me right off. I’d listen to bands like Opeth and Beyond the Buried and Me more often if the growls weren’t present.

If you’re looking for metal with cleaner singing, I second the suggestions for Unleash the Archers and Nightwish. I can also recommend Blind Guardian, though the singer’s voice is polarizing. One of my favorite metal singers is John Bush from Armored Saint. He also did a few albums with Anthrax in the 90s.

For instrumentals, I can’t recommend much aside from guitar virtuosos like Steve Vai. Occasionally bands will release instrumental versions of their songs as B-sides, bonus discs, etc. Might be worth checking into.

I mostly listen to death-doom rather than strict death metal, but there’s a fair bit of that out there. My two faves in the genre:

Draconian has clean female vocals alongside growled male.

Swallow the Sun has a wide range of vocal styles, but getting increasingly cleaner pretty much every album (along with clean female vocals on a lot of tracks).

Again, this is death-doom so a lot of the stuff will be a little slower-tempo than straight death.