For those still experiencing this issue and are curious as to why, I just came across the following MyBroadband article: MTN secretly throttling uncapped 4G in South Africa, posted last week:
https://mybroadband.co.za/news/broadband/607525-mtn-secretly-throttling-uncapped-4g-in-south-africa.html
I've had the exact same experience on Afrihost's Uncapped Pure Fixed LTE (MTN) since, I believe, the start of August:
6Mbps up and down between 12:00 and 00:00
30Mbps up and down between 00:00 and 12:00
So the only solution is to buy a supported 5G Router? Even if 5G service isn't available in...