I finally finished it! That was incredible amount of work. Whatever are people charging to do this - it's too little!
In the end I went through:
14sqm of vibro damping - 9sqm of 2.3mm and 5sqm of 1.8mm
9m2 closed cell foam - 6m2 6mm and 3m2 8mm
8.5m2 open cell foam - 6.5m2 7mm and 2m2 15mm
6.3m2 acoustic barrier
I have probably 0.5-1m2 of the 8mm closed cell foam left over and almost nothing of the rest. I wasted very little material - none open cell foam, probably less than a 1/3m2 butyl vibro damping.
The result is just WOW. It's like somebody turns the volume way down when I close the doors - kind of surreal. Very little outside noise gets inside. The diesel engine is way quieter and I can barely hear the 3" exhaust.
The tyres are still loud

My biggest goal in this was to have silent MT tyres and they are considerably quieter than before, but still scream at 130kmh... Maybe if someday I remove the dash and do the firewall I will be able to do something about them, as it sounds like most of the tyre noise comes from the front. Every creak from the trim is super loud in that silence, so I will have to redo some of the panels.
My amplifier is drowned in mud so no idea about the music yet. The bluetooth speaker sounds about the same
Cross section of the 3 layers on the floor
End result
I had some surface rust on some of the seat brackets and all of the centre console brackets, so acid dip to strip, then epoxy primer, urethane paint. The console brackets are always rusty on all photos I have seen - why?
I came up with a more optimal distribution of the open cell foam in the door cards. You can fit a lot in there and pretty thick too. The only place that interferes with the door is the flat section next to the speaker hole on all doors. I wasn't able to fit more than a single 7mm layer there.
The wheel arch covers are the only piece of the interior that I had trouble fitting back, so I cut the bottom edge. It doesn't press the carpet that good any more, as I was hacking at it until I could put the covers back without measuring too much, but it is not awful. No space for foam on top of the arch due to the layer of materials I have put there.
More open cell foam in the rear windows trim piece
I was able to fit a lot of foam on the roof too. There is plenty of space behind the rear AC vents and between them and the sunroof. 20, maybe 30mm at some places. 10mm underneath the vents. Lots of space above the front windshield too, underneath the sunroof mechanism.
I did the hood too. Can't say there was much of difference from that. Engine noise seems to come mostly through the transmission tunnel.
Put the final piece of trim and carpet in 6am and at 11 I already was sliders deep in mud after a 3 week hiatus.