You will never have a true representation of upload speeds over a wireless network, we're with Virgin Media, have the maximum speed we can have, 360mbps and on my main PC which is wired into the Hub, it will achieve those speeds (easily) where as my phone, a Samsung Galaxy S9 "barely" achieves a third of that speed and that is when I test it four foot from the Hub.
All running concurrently? That's actually quiet a bit of strain for that speed.
Anyway, if you rang into me when I used to work on a level one helpdesk for an ISP, my first thought is, how long has it been like this, when was the last time you reset/power cycled and if the diagnostic tools said the connect into your home was fully functional, are you or were you being effected by the storm that was effecting large chunks of the UK today.