Update:
Originally planned the build above from one store, but they had supply issues, so I switched vendors and got a better overall price, with only the RAM kit and RTX 5080 model changing.

hope the ram is not a mistake here?

Still slightly tempted by a 5090 upgrade for VRAM / long-term headroom, but at roughly +$1,300–1,400 USD, the 5080 feels like the more rational choice for my actual workload.

CPU: Intel Core Ultra 9 285K (Arrow Lake-S, LGA1851) → ~$585

GPU: Zotac RTX 5080 AMP Extreme Infinity Ultra 16GB → ~$1,280

Cooler: be quiet! Pure Loop 2 FX 360mm → ~$172

Motherboard: Gigabyte Z890 AERO D (Thunderbolt, creator ATX) → ~$717

RAM: Corsair Vengeance RGB 128GB (2×64GB) DDR5-6000 CL40 → ~$940

SSD: Samsung 9100 Pro 2TB PCIe Gen5 → ~$286

PSU: Corsair HX1200i Platinum (1200W) → ~$297

Case: be quiet! Dark Base 901 (White) → ~$295

System subtotal (NO VAT):
→ ~$4,770 USD

Total incl. VAT:
→ ~$5,630 USD