Where and how are you testing your speed to know you've gotten 48Mbps, 8Mbps or even 3.8Mbps? None of the speeds in the link you gave reflect that.
It's also better to use a support community for its intended purpose rather than to post offensive comments and insults. If you're just here to complain and then insult anyone who doesn't see things your way, social media is that way... -------->>>>>
If you're here to get help, I suggest waiting for the reps to reply to see what they can do to help, but the one thing they cannot do is make beam and/or system congestion go away, even though you've already completely dismissed that as a possible cause. The reps are on M-F from approximately 9AM to 6PM EST.
For reference, try temporarily turning off your anti-virus when running speed tests at testmy.net, as this may be causing the skewed results. That's not a definite, but it's a possibility. Some AVs do.