Nokie Gateway Sudden Packet Loss

This has just started happening to me as well 3-4 days ago. 

Until 2 weeks ago I had a previous generation router from Nokia - 5G21. It worked well for 10 months. I was getting about 200-500 Mbps download, and 20-60 Mpbs upload (depending on a time of day). 
I switched my cell provider from Verizon (5 lines), to T-Mobile MAX plan. There was an issue with my account when merging home internet with cell service, so they closed my home internet account, and opened a new home internet account under my cell plan ( to get 20$ off discount for Max plan holder).  I Returned the Nokia 5g21 gateway and got the new ARC KVD21 square box. What a mistake!! 🤬

My speeds dropped 10x since the switch. I now get no more than 20-40 Mbps on average ( 150 mpbs if I do speedtest in the middle of the night) .  However while being super disappointing, that's still acceptable for day-to-day work from home stuff, and basic netflix in the evening.

If I hold my 5G iPhone next to gateway and run a speedtest - I easily get 200-300 Mbps. So I know the tower is capable, and location for the router/gateway is good. 

WHAT IS NOT ACCEPTABLE IS THE 5-15 % 😡 packet loss that started happening 4 days ago.  

1. I can’t use Zoom for calls.
2. My VPN to work disconnects constantly.
3. I can’t run a simple SQL query against work DB server, without loosing my connection multiple time.
4. My Wife’s connection is dropping constantly - she can’t use online conferencing tools either. 
5. Kids can't do homework properly. The list goes one.
6. 🤬🤬🤬🤬🤬🤬🤬🤬🤬

I've been in IT for 25+ years, 10 of those doing Network/DB admin & User Support. I know how to do basic troubleshooting 🤓

1. The issue has been isolated to gateway and nothing on my network . 
   1. I confirmed it first then spend 2 hours with T-Mobile level 2 support confirming the same
   2. Connecting directly to Nokia/T-Mobile gateway doesn’t change the situation
   3. Factory reset doesn’t help
2. My unifi gateway monitors my ISP connection, and I’m constantly getting reports, that my internet has disconnected. 
3. Support engineer placed an order for replacement router. I just got it. 
   1. NO CHANGE IN SITUATION. 
4. What is going on T-mobile network that these ARC devices are not working well?
5. Or is it my account?

WHAT THE HECK T-MOBILE??🤬🤬🤬

Should I go back to Verizon & Comcast?