RBR750 dropping internet connection over ethernet

Thanks Furrye38 for your suggestion. Was on the phone with their 1st level support most of the day as this was initially my 1st suspicion. However, they could not find anything suspect along the service line to the ONT and I was able to rule out any issue from the line into the house testing with a 40gb download after bypassing the router, going direct connect from line in to the house to desktop, which completed successfully. After testing, powered off Router and Sattelite, rebooted ONT manually and left ONT disconnected for 3 minutes for a clean reset, then reconnected while leaving RBR/RBS750 disconnected for 10 minutes, then reconnected and powered back on. Once router and satellite were synced, retested again with a 5gb file download this time (connected desktop to router via ethernet) and it crashed within the first 1gb of download (internet dropped out, light went solid magenta on router and only the router oddly I must add). When this happened everything on the network that was connected dropped immediately, no matter wired or wireless and was unable to login to admin portal nor get connectivity back until a hard power cycle of the router. I was able to replicate this 2 additional times thereafter. Streaming was not impacted though, on my wireless devices (Rokus) if just doing only that. Seems to be only when trying to download anything while wired to the router. Tried also downloading another smaller file to my work laptop (app update pushed out) and it crashed again as well after ~300 MB's downloaded. Performed various speed tests throughout, but only mentioning in case it helps (from router to ookla average - 615 down 930 up, bypassing router direct line in from ONT to ookla average - 920 down, 930 up). I am also using mac filtering via access control which I forgot to mention, if this helps at all.