What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too? Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended.
What channels are you using? Auto? Try setting manual channel 1, 6 or 11 on 2.4Ghz and 40 to 48 channel on 5Ghz. Any Wifi Neighbors near by? If so, how many?
Try disabling the following and see: Armor, Smart Parental Controls or Circle, Traffic Meter.
There is no beta FW for v1 RAX120's. Beta mentioned is for only v2's with random reboot issues. Doesn't solve any wifi problems.
My Setup | ISP SparkLight | Internet Cable 1000↓/50↑ CAX80 Modem Mode | Wifi Router RBE971 | Switches NG GS105/8, GS308v3, GS110MX and XS505M | Additional NG HW: C7800/CAX30/CAX80/CM1100/CM1200/CM2000, Orbi: CBK752, RBK50, RBK853, RBK752, RBK953, SXK30 | NightHawk: MK63, MK93S, R7000, R7800, R7960P, R8000, RAXE500, RAX120v2, RAX50v2, XR450/500/700/1000,
