Xbox Series S download speed slow, but other devices fast.

So I've looked for answers everywhere on this subject and none so far have been satisfactory.

I currently have my Xbox Series S connected through WiFi to my router. My phone in the exact same location when speed testing will get 90-100mbps speeds, but my Xbox will only get about 35-40mbps when performing Xbox network tests and Ookla speed tests. Why is this?

I've noticed a lot of people asking the same question and they're told to reset the Xbox etc etc., but this does nothing to help. Please I'm not looking for the same repeat answer of reset the Xbox or reboot the router. I would also get an ethernet connection but sadly this isn't possible, and at the end of the day if my phone can get 100mbps on the WiFi, then my Xbox should too.

Any new ideas to help fix this would be much appreciated. Thanks!

:)