I have Verizon Fios 50/50. For the past 2 weeks, my speed tests on my macbook pro were more like 5/5. After reading another comment about NordVPN, I deleted my wifi settings files and deleted NordVPN and my download speed shot up to ~50 mbps but upload is still only 10 mbps. I have a feeling this is related to VPNs that I use even though they're not active. Deleted NordVPN seemed to fix my download speed. I haven't used Nord VPN for 6+ months so it was not active at the time, which is confusing. I used Pulse Secure and Cisco AnyConnect on and off for work so unfortunately I cannot also delete those VPNs. Anyone have any ideas? FYI - my phone sitting next to me on the same wifi network has consistent 50/50 speed tests.
I booted in Safe Mode and internet speed was normal. I also found another thread that solved the upload speed problem (apple.stackexchange.com/questions/359723/…). Apparently, my PulseSecure VPN client installed a kernel extension that was an issue. Not 100% sure if that was the issue but after following the instructions on that thread and rebooting my computer, my speeds are up to 50/70! after weeks.