5G Home Internet nightly slow down

Sorry friends, I forgot to update when this got resolved. Here's hoping you can dedicate the time it took me to get this resolved (if what I did even affected the results).

What I did that was extremely time consuming was I constantly called and chatted customer service the second it throttled or slowed to the crawl. I called and called and argued and argued. After about three days and seriously considering cutting back to my old plan I was told to send my unit back. I drove to two T-Mobile stores and forgive me but it's been almost a year since then and I can't recall if they shipped it for me in the store but I recall a distinct displeasure of dealing with the store personnel. Either way, the old unit went back to HQ and I got a new one in the mail 2-3 days later.

I made a call to the local store to ask about coverage and they said they don't offer home internet at my address when I in fact had a gateway running previously AND a new one on the way from main customer support. I'm not sure if they had beefed up the tower and were previously shifting to the Narrowband 5G cell beam in the evenings while they did work previously. But by the time the new gateway came in my speeds were solid and I haven't noticed any issues.

If anyone wants to doubt my credentials and ability to troubleshoot, I've worked in IT and communications for 12 years, all 12 of those doing majority wireless transmission work and 8 years networking experience. I'm very well versed in transmission of information, so no it wasn't an IP setting on my laptop, it wasn't the WiFi frequency of 2.4GHz or 5GHz. It wasn't band overlap with my neighbors WiFi. It was not a throttling on my PC to conserve resources. It had to be something on T-Mobile's end, but it's resolved for me now.