EAC detected a problem and kicks me. Due to VPN?

(Before anyone asks: Yes I tried the EAC support site but it was of little to no help for me.)

TL;DR - Are EAC kicks caused by the use of a VPN? If so, how can I play online while remaining connected to a VPN, if possible?

So I just recently subscribed to ExpressVPN, and until recently I’ve had no issues playing matchmaking with it.

But then I got a new router compatible with ExpressVPN’s app - specifically, the NETGEAR Nighthawk R6700v3, and installed it on that. Again, no issues with matchmaking after doing so (although there was one time when I was unable to sign in to Xbox Live in any game on my PC).

It’s only just over the last day or two when the error started happening. Match begins, and about 5-6 seconds later I’m kicked with the message “YOU WERE KICKED - EAC has detected a problem. Go to (EAC support site) for assistance in resolving this problem.” with every match. The VPN immediately jumped to mind as a potential cause, as it’s the only major change I’ve recently made to my network. The ONLY other thing I can think of is switching the ExpressVPN protocol to Lightway UDP, which has resolved some of my non-Halo issues with the VPN.

Things I’ve tried since then:

  1. Adding my PC as an exception to the router VPN, then using ExpressVPN’s app to connect using a VPN.
  2. After doing 1, adding Easy Anti-Cheat’s EXE as an exception (so it doesn’t use the VPN).
  3. After doing 1, adding Halo MCC’s EXE as an exception so it wouldn’t use the VPN either (unfortunately I was unable to access the WindowsApps folder, and trying to do so in the past has resulted in game/app corruption that needed a complete Windows reinstall to fix).

I can understand VPNs being used to cheat, but I can promise you I have no malicious intent. I just want to play the game.