AX3000 is quite unstable while playing videogames

Hello, I used to have a older router with you guys and everything was just fine. I increased my internet speed and needed an upgrade in order to use my new and faster internet connection (300/10). Before with the Archer c50 my ping while playing used to be not the very best but it will stay on a constant value during the whole gaming session. But now with this new piece of equipment I cannot play. My ping jumps from 80 that used to be before up to 500 very often (like every 5 seconds or so). It´s sad that I made that investment thinking that the AX3000 was going to be a better experience with the Gigaports that it has. (I play on PC using a highspeed ethernet cable). But it seems that this router is just not good enough compared to the older devices that you guys used to made. Btw the old modem with the new internet connection works just fine, so it must be this new modem.