RAX75 bad buffering for Playstation 4 need help

Just bought an RAX75 from Costco and having new problems with PS 4 and bad lag spikes, please help.  I have frontier 1Gig internet service.  The Playstation 4 is ~25' from the router and default connected to 2.4Ghz channel.  I am hoping there are some settings I can modify etc to fix this otherwise I am going to return it.  Funny thing is I had a tp-link deco m9 mesh and got rid of it for this RAX75 but I am starting to regret it.  I got rid of it because the signal was weak for my iphone in master bedroom which ironically is not the case for the RAX75 but I never had lag spikes or buffering on tp-link and now i do with RAX75.  I was thinking maybe it was due to the PS4 being assigned to 2.4ghz line but i dont know.  Smart connect is On.  Firmware is up to date 1.0.3.88_1.0.41. Tried to enable QoS but apparently there is a bug or something.  Speedtest says 908/745 in qos menu but when I select enable Qos it says no new database available and leaves QoS disabled.   Please advise my last resort is calling tech support before I return and look for something else.