Nice Base you got there. But giving the history of DDR-Number Changes dimishing return has hit hard the last couple of gens. SD to DDR or DDR to Dual-Channel DDR2 were huge boosts. But DDR2 to 3, even 3 to 4 were.. lets say less impressive :). Lets get through your Stuff and i try to give my best answer. I was head of PC-Manufacturing (mostly build to order stuff) for quite a while, so i´d say i dont have a "fanboy" opionon, rather a good "cost to perfomance" or "doesnt make any sense" view of things. Lets get to it.
amd 5950x Check, bought that already :).
rx 6900xt Check, bought that already :).
Motherboard:
ROG crosshair viii dark hero x570
Besides beeing one the the most expensive ones? what do you really get from a High End Mainboard like this? You said Gaming and Music. So no hardcore OC? in this case you really dont need this kind of Motherboard. Any Premium X570 would suffice to get an decent overclock with ryzen master out of the CPU so you could game 24/7 without any stability issues. You can save about 300 bucks here without loosing a single FPS.
Invest this money in:
PSU:
One the most cringe parts of my job. Seeing a 3000 €/$ PC with all the finest parts money can buy either with a humungus 1400W PSU (because...) or a dirt cheap maybe 80+Bronze... Get a 750W Platinum PSU, 94%+ Upwards. They can handle any sudden load your config with throw at them, they are silent when you browse and your Energy Bill will be lower. But good PSU cost a lot of money without adding any FPS. But saving here is so wrong. Trust me.
Soundcard?
Not my Area of expertise so i cant comment here.
Case?
Anything with a good Airflow. Clearance for E-ATX Boards, huge ass GPU and Cooling is always nice. Corsair, NZXT, Coolermaster, pick your poison. If you plan on using good Case Fans get one with no Fans included, you will most likely switch them anyway.
Cooling?
Noctua NH-D15S or any other NH-D1x Tower Variant. No need for a 300€ AIO if you can get the same cooling with less maintenance and equal to less noise. Also switch out as many Casefans to Nocuta ones. They look terrible, but are THE best out there.
Ram?
Get your Hand on a Set with Samsung B-Dies (google it) with whatever size you need.
Storage?
PCIe Gen4 x4 NVMEs - as many as your Mainboard of choice can support. Samsung 980 PROs are a good choice here.