TrackNotes

There is also a boxiness that builds whenever the horns come in, clearest around 1:14, somewhere in that lower-middle region where warmth turns into cardboard.

A small, narrow cut there would open it out.

The hiss I would leave alone, personally, it is part of the character, and chasing it tends to take the top off the horns with it.

At the moment the compressor is doing quite a lot of work on the loud lines, and the quieter ones sound like they step back a little as a result. Something you could try:

level the takes by hand first, line by line,

so the vocal is already fairly even before anything is compressing it, and then let the compressor shape the tone rather than rescue the balance.

Structurally this is sound. The loop is varied enough with the filter opening and closing that it never feels static, and the drop to just bass and voice at 2:34 is the best-judged moment in the track. The only thing to be aware of is that the jump coming out of it is quite a leap in level, and a mastering chain will flatten some of that.

If you wanted to protect the drama,

it is usually better to bring the loud side down than to push the quiet side up.

On the busier tracks, track 3 especially where you have those thin bell lines carrying a lot of interest,

you could try laying a single-note drone underneath,

in the key you are writing in: either one note or the root chord. They do this a lot in Indian classical music, starting with a one-note drone and improvising everything over the top, so there is always a harmonic foundation holding it together.

The murky, submerged feel is the strength here, not something to clean up. There is a lot going on harmonically, and the tracks move through distinct phases rather than riding a single loop, so they read as composed pieces rather than beats.

The little tempo shifts, dropouts and bridges in the arrangements are the best thing about the project.

That developmental quality is exactly what carries instrumental music that has no vocal to lean on.