tuned now.
Just so you know, if a single sound is muddy, it's not a mastering issue, it's a mixing issue: You can't redefine the balance between different elements in mastering.
but anyway, I'll comment as I listen:
The intro is very quiet, would be hard to mix when you can't hear it proper from the booth control. Very nice arrangement tho, proper rainy day material as you said, big ups for that. I really like that more musical approach to drum and bass.
The kick really drowns under the powerful sub mat. Maybe you could beef up the kick and sidechain the bass to it. I think you'd have enough room even without the sidechain tho as the tune is so airy.
I also left wanting for some edge to the hihats, maybe just 1 hit per bar to give it some groove. Same thing with the vocal, I can't really make out what it is. Give it a boost at 1000Hz and maybe 2000Hz too and see where that leaves you.
Would work pretty good as an intro to a LP if you leave it at the breakdown at 4 minutes. Cherish this one with that aim in mind I tell you.