Firstly you do not want to be running speed test while on a VPN. You will never achieve the same speeds as if you were not using a VPN.
Second you might want to remove the wireless extender if it is not hard wired and run another test, with the main Wireless Access Point.
If speeds look good while on the main access point you might want to consider hard wiring some Eero devices, instead of using an extender.
Non hard wired extenders typically cut your speeds in half, then adding multiple devices to the mix speeds will continue to degrade.
While testing you may also want to turn off as many wireless devices connected to your access points to see if it makes any difference.