I've never had a problem with my guitars' high-end competing with cymbals, but then again, I've laways used pre-mixed cymbal samples (Steven Slate Drums). Although, TBH, his cymbals aren't very well-regarded. They do sound kinda thin, TBH.
I do undestand your approach to mixing is different than mine. You seem to go more for a tight Thrash Metal aesthetic, and I go more for a Swedish Death Metal aesthetic.
I don't really like narrow-sounding guitars in Metal, personally. I've not really spent much time judging other genre's productions. I do know, for example, I hate Fluff's approach to dialing in his tones. He seems to go very light on bass and very heavy on mids.
Fluff's sound to me is pretty thick but he writes what I called "dad riffs." It's very Godsmack-ish. Sully Erna used to work as a contractor I think, so I call it "carpenter rock." Beards and flannel. It's for guys who like to write riffs in drop tunings but don't do Paul Gilbert style stuff, which, despite its age, is still useful for developing alternate picking chops and doing something slightly more advanced--say Amon Amarth.
Fluff is super pedestrian. I can't think of a single original song of his. He's a guy who's famous because he makes videos for Gen Z kids wanting to learn recording, so he gets his name put on plugins, sample packs, and whatnot. Next thing you know he may try a guitar company. He's an influencer, not a real musician or recording artist.
Compare this to Kiko Loureiro who did his stuff in Angra and now Megadeth and puts out instructional guitar videos of real quality. Dirk Veurberen as well (loved Dirk in Scarve and Soilwork, although he doesn't put out many videos anymore).
YouTube guitarists/producers are essentially gear/software selling infomercials. Why should I buy an impulse response pack from one guy when another guy is selling something nearly identical, or I can just find free, open source IRs? That said, they're usually of a younger generation who weren't old enough to record/tour in the 90s, the last time metal music was truly marketable in terms of album sales. "Metal: A Headbanger's Journey," might have shown this extend to 2006 or so, but the scene went underground again not by being buried but by there being so much content published online that good bands were hiding in plain sight.
Also by Swedish death metal, I think a lot depends on Stockholm vs. Gothenburg. Stockholm sound like old Entombed is a lot more raw. Gothenburg mostly sounded more polished but the bass in those mixes is in there more as a glue than as its own thing. I did think it was interesting in the mid 00s when Ola Flink of Soilwork was using Gibson basses. He had a really up front, vintage tone for a time.
Relative to 80s thrash metal, thumpy, felt kicks are getting more massive and clicky all the time. Double bass and blast beats used to be rare things used to impress. Now they are on all the time. Meanwhile guitar wants more low end, but tight low end. Between those two there really isn't anywhere for the bass to stand out, IMO.
It's not quite at 80s levels, but I think the bass in a lot of modern death metal is pretty suppressed in the mix, mostly to showcase the kick and low end of the guitars. It's heard as far as it is felt, but instead of hearing a distinct instrument, with the bass you're hearing a bridge between the kick and low end of the guitar that holds everything together.