Ok. So I got my hands on one of the very rare 7950X3D and installed it together with 6000 Mhz CL30 RAM on an X670e mainboard with Radeon 23.4.1 drivers. This is really a boost! I get stable 10 FPS more in VR than I had with the 5800X. Works really good! 40 on the ground at a busy airport with FSLTL enabled and about 50 FPS at cruise level - with the Fenix! TLOD still at 150, OLOD at 100, OpenXR 100, Render Scaling 100, HP Reverb G2, ambient occlusion off, DX12. The rest more or less at high level. OpenXR Toolkit foveated rendering set at quality preset. I am very happy with this performance.
Some people do not get expected performance with this chip. I think the most important thing is to do a BIOS factory reset after installing the newest firmware. And installing Chipset drivers and game bar of course.