I'm guessing you're using the PTC on the Quest 2. If so, this was an
issue for me as well. It seems like rebooting it multiple times had
worked for me though.
It's relieving to know I'm not the only one with this issue. I had also
downloaded various games and files and the speeds were far more normal
in comparison to the PC app. Running speed tests show I have around
700mbps in terms of internet connection...