All banners other than plain colors have not worked since the initial beta release to the current 1.19.31. This is one of the most glaring bugs with RTX right now, as there is no way for a player to even temporarily resolve the problem for themselves.
I am hosting a server and running the vanilla RTX pack on my 3070, I too can not see anything more than the base color of patterned banners. However, my server does not crash when I place/break the banners.
All banners other than plain colors have not worked since the initial beta release to the current 1.19.31. This is one of the most glaring bugs with RTX right now, as there is no way for a player to even temporarily resolve the problem for themselves.