I have just purchased a intel ax210 and installed to my laptop. Upon installation, I have try to connect my ax router and run a speed test in which only 1Mbps under 5Ghz wifi. However, the speed was increased to 54Mbps when I connected to a 2.4Ghz wifi under the same router.
In addition, I have checked the properties under 5Ghz network that the speed is 700Mbps
There is a lot more information needed to assist you with this. Did you verify via the laptop compatibility that your laptop will support the AZ210 adapter? What type of wireless router do you have? What is your Internet speed - upload and download speeds?
I am attaching a link to the Intel System Support Utility, The output from this gives a detailed insight of your hardware and network setup. Please post the results with your answers to the above questions.
According to the specs for the Thinkpad X280 there was an optional wireless M.2 module, AC-8265 dual-band and Bluetooth. Did this Thinkpad ever have that module running? If so, did you remove the AC-8265 software when you added the AX210? Did you check the compatibility of the motherboard (or Thinkpad X280 in general) to see if the AX210 module is compatible? What is the approximate distance between the Thinkpad and the Netgear router? What types of objects are in between (walls, doors, etc).
Does the Bluetooth work, as in you are actually able to pair the Thinkpad with another Bluetooth device? If so, how close were the devices when paired?