A common misperception is applying the SpeedTest like you are using and applying results to livestream uploading. That test explicitly ignores momentary glitches and reports a best case high average.... whereas Livestreaming requires a given bottom threshold, with consistent bandwidth and latency (lack of jitter)
That SpeedTest does NOT measure such things. So you may, or may not have, 8Mb/s, or even 5, to use for upload
WiFi may work, or may not depending on your specific environment. WiFi could easily work for watching streaming video (which all have buffering built-in) and NOT work reliably for Uploading... you could easily find 5Mb/s working sometimes and not others... such would be normal and natural (not what you would want, but how the tech works). I've save you the long technical dissertation on why this is the case.
such challenges with WiFi has been discussed here and elsewhere extensively (feel free to confirm with your own research)
If you have to use WiFi, so be it, just temper your expectations. If you want consistent, reliable, and/or performant, use a wired Ethernet connection.