Man, labels are hard, and rock and metal have a ton of overlapping ones, making it even more difficult to see what it going on.

Here is my two cents: it is more about the influences, what the band itself claims, the general public consensus and the history rather than about the music itself. In my mind, two bands could play the exact same music and be classified into two completely different categories if the extra-musical elements are different enough.

Here are some examples I have on the top of my head:

• For an example you gave, AC/DC is generally classified as hard rock. I feel this is mostly because their were there “before” metal was a thing, and eventually they stayed in that category even though they could have had been classified elsewhere had they appeared later (Airbourne).
• Similarly, many people put Black Sabbath in the NWOBHM, even though the music style doesn’t match. Today we’d rather classify them as doom metal (many people do).
• Motorhead always claimed to play rock’n’roll, yet most people put they under the tag “speed metal”.
• Bands like Ulver or Alcest would probably not be classified as metal at all with the music they play today, but they are because of their black metal legacy.

The claim that “anything that isn’t death or black isn’t real metal” seems difficult to hold to me. If you want to talk about “pure” metal, i.e. without external influences, the heavy, thrash, doom and power -at least- should be included imo.

I don’t know enough about some of the bands that you are talking about in your post but another point that might help you is about the term “heavy metal” itself. In my mind, that that is again only my opinion, “heavy metal” is a tag that includes an aesthetic and a style of riffing and composition particularly attached to a period (1980’s), but the “heaviness” of the band is not a criteria at all.

Eventually, it also comes down to the way you feel about a band. If you think that a band should be labeled in a way, because they make you think of other bands labeled in the same way, nobody can stop you. ¯_(ツ)_/¯-

I’m currently running Alpine on my RPi4 as a host for some Dockers, including pi-hole and it works great! The setup is surprisingly painless and you’ll end up with some insanely fast boot time. Highly recommended !

I’ve been trying Librewolf as a Flatpak on my work machine lately and it’s going great! It’s really a no-BS Firefox + privacy settings by default; love it. But in general I keep the default Firefox that come with my distro.