The only thing you need to know (generally) about replacing the wifi card is whether the laptop/device has two antennas or three (virtually all systems except for the very newest ones have two antennas) and whether the existing wifi card uses pcie or cnvio. CNVio is only on Intel CPUs to my knowledge and those cards can only be replaced by other CNVio cards, while PCIe cards are far more widespread.
Newer 2-antenna wifi cards can still do 6ghz over one of the antennas but will not do 5ghz at the same time. Which frequency to use will depend on what the the access point supports. The other antenna will always do 2.4ghz for bluetooth and longer range wireless. 3-antenna systems can do 5ghz and 6ghz at the same time though this more affects wireless benchmarks and is unlikely to result in anything that an end user can notice.