The link quality seems ok, though it could be better.
Considering that upload speed seems only slightly reduced, one more thing you could try is to access the device's WebUI, go to Network -> Wireless, press pencil icon on Wi - Fi access point interface to edit its settings, disable WMM Mode, press Save and apply.
Could you check what speeds do you get when you connect your phone to your home router?
It would also be interesting to check if the issue repeats, when you are connected to a different Wi - Fi WAN source, not your home router.
Also, you might have already done it, but please double check antenna connectors if they are properly screwed.
Best regards,
Žygimantas