Packet loss even with new RMA unit
I have submitted a support ticket but I was hoping the community can respond faster or help me trouble shoot. I have the TP-Link Archer AX21 router and the Netgear CM1000v2 modem. I have Xfinity as my provider. I recently just got a new line installed from the street and a new line in my house so that is all good. I noticed packet loss (games will say latency variation) so I investigated further with ping plotter. I was losing a large amount of packets on hop1 which has to do with my local network aka my router. Before anyone asks yes I have tried multiple different high quality Ethernet cables. When I plug directly into modem I receive no packet loss and everything is fine and when I connected an old router I also received no packet loss (I did start to receive packet loss with old router as well once I restarted the modem recently today). Well everything was working with old router until I tried same RMA model they sent me and once again packet loss. Somehow this now has made the old router also not work and have packet loss. I have gone through all the network configurations I can think of. While I did do static IP addresses it didn't work but I would also prefer to get dynamic working anyways because that is what Xfinity recommends. I have also of course tried on multiple devices.
So I'm at a point where I have tried everything and since I used the new model now my old router also has crazy packet loss. I'll attach some ping-plotter pictures to help show the issue. I am at a point however where I do not think it is a hardware Issue and it is either the way the network is configure which might include ho Xifinty is automatically assigning me IP's.
Any help would be greatly appreciated.