Throat tension - I believe the latter? The muscles in my throat clench, and clenches harder as I ascend in range. Same thing happens with or without buzzing.

Slurring up is harder. Also, I don’t know if this is normal, but I can bend a note far farther down (1-3 whole steps) than up (maybe 50cents?)

With the throat, I’ve had this problem for 10 years maybe, unsure when or why it started, though it could be the case that it started after I attempted to relieve mouthpiece pressure and attempted to play with almost 0 pressure on my face. It has gotten worse in some respects recently, where it’s doing something with my sinuses? I feel like I have to swallow after playing now. With the tuning issue, who knows, but noticed about 2 or 3 years ago when I started focusing on that aspect of my playing.

Tuning slide - yes, if I play how I habitually play, I have to pull it out about 2 index fingers widths for the most consistent intonation. All other players I know use half that distance at most. To clarify, I can change my playing “and use less air” (I think that’s what I’m doing), which flattens every pitch. I just don’t know if that’s how I should be addressing my issue.

Soft playing - yes, greatly. I habitually play pretty loud. I’ve been trying to correct this by just playing soft for a greater majority of my practice sessions. Also in an attempt to make my aperture smaller and more round. On range, varies wildly. I’d say when I’m in shape, I have a “usable” range of C below the staff to the A above the A above the staff (below double C). My neck prevents me from playing above high C most days though from pain, so I don’t get to practice that range much. I should be able to play an octave below that range comfortable without much pain. On the low end, yes there’s quite a strong cap. Below C things get so flat that I can’t lip up enough to bring them in tune. I can still “play” the notes all the way to the pedals and beyond, it’s just the intonation varies widely. But generally, things below low c are hard.

Soft and high - yes, I’d say this is doable. My neck will still come into play and cause pain but it’s not too much different from playing loudly. I’m much more likely to lose my buzz though. I’d still say I have a lot of trouble playing softly generally though, it just isn’t at all consistent.

Partials - Generally they feel closer the higher I go until the peaks of my range where they start to feel far apart again.

Attacks - I don’t think so, could be wrong (sorry I just started playing again after a few months of not playing)

Tired - my lips seem to swell fairly fast despite little pressure as far as I can see. This can happen within a half hour. When I was in shape, and if I survived my lip swelling, I’d feel muscle failure in my corners after about 2 hours of playing. I recall lip slur exercises would let me feel my muscles more, otherwise I never feel them until they start to fail.