@Solla-topee I did those except the quick setup part IIRC, but I'll re-try everything in the same order when I get the chance. Thank you.

I have bought a RE450 to extend my wi-fi range to the upper two floors of my home, my VDSL line and modem (Zyxel VMG3312 that my ISP provided, I suspect not a good signal booster) is on the bottom...