Well would you look at this......
So, not 100% this but game freshly reinstalled on nvme over my sata ssd, same settings as per before. So either a fresh install fixed the textures or/and a nvme drive does help with texture loading (given consoles have nvmes and games are designed for consoles, wouldn't be surprised if some optimisation issue here)
Obviously there is still an issue there with vram, be that not enough for 4k with max settings and no FSR or/and some work needs done with the management side of things, which I am still leaning towards, especially after seeing these results now.
SATA SSD, my old post in here:
New screenshots with the NVME:
Noticed the much improved texture with the flame thrower gas tank straight away, sadly didn't have any screenshots from me before but there are plenty on that ubi thread where people posted the same issue.