extremely slow WAN speeds

So i bought this router to see if it would have with my routing to Destiny 2 servers . When i was running the setup it initially said i had 117d/13.4u speeds. then shortly after i had to update firm ware. after that i noticed m,y wired sppeds drop completely. i was getting 1-1.5d/0.02 up and everything was impossible and barely loading.I didnt change a thing it just instantly went to nothing.i tried all 4 ethernet ports and nothing still changed. so i did a factory reset thinking it was the firmware. well apparently the firmware does not reset so i went and exchanged for a new 1 to see. then new 1 did the same thing during setup. initial DL speeds was 116 and uplaod was 11.6. then it went to firmware update and wouldnt let me not update it. but i just exited outta the program and waited awhile. eventually it let me in the mainscreen with original firmware . But my wired connection literally went back to nothing. was gettin 1-1.2 DL and 0.01 or nothing on my upload speed and woulkd literally just time out. my ping to w/e server using speedtest.net was 2000 when it would actually work. i havent changed any settings, my other router i have ac1750 r6900v2 works fine. i had this issue with a firmware update but just reverted back to a different older firmware and it works fine. really just want this router for the dumaOS. but looks like this whoole systerm is flawed. i just dont understand how initially its tell me my DL/upL speeds are fine and then a few mintues later it is garbage, while my wireless speeds are completely fine....any suggestions