@Efe Çetin
I have tried this before, but I think there are more changes that has to be made for 5b. For example the pcie power is set to 1.8v instead of 3.3v https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5.dts#L82-L91 ... I'll try some changes if I have time this weekend and I'll let you know.
Thanks.