KDE Neon no display

I installed 20241215 ISO KDE Neon & all updates on family desktop PC… gets no display (even no console, just black screen) without recovery mode (loads VESA display driver). Our PC is the following.

  • Intel Core i7 7700K CPU
  • GigaByte GA-Z170XP-SLI system-/logic-board
  • 64 GB Kingston HyperX DDR4 SDRAM
  • ASUS Rog Strix Radeon RX Vega 64 8GB OC display/video/graphics card
  • Dell UltraSharp 3007WFPT LCD monitor (2560x1600 resolution)
  • standard, low-latency kernels (will list if asked)

Radeon RX Vega is seven years old, and 2560x1600 resolution was used 21 years ago, though unpopular after 2008, the shape (8:5) became popular again by 2020.
We don’t have the problem on any other GNU/Linux (I use many).