Strange spike lags

[Anto_2000]

I got some strange spike lag only when i play on cod since a week for no reason, i tried game on pc, ps5, xbox with different cable for each device (I changed also the router ethernet port)  and even on wifi, but I still got spike lags . My network system is a ISP modem/router and xr1000 linked to isp router. Every device is connected to the xr1000. I set qos in the right way and it worked well for 9 months. I tried playing on isp router and the spike lag are gone, so I guess the problem is in xr1000. xr1000 IP is set in the dmz zone iof isp router. reset the router 4 times but spike lags are still there. Even if only one device is connected i got lags. I played phasmophobia on PS5 and spike lag are gone. I don't know what's happening