2 months of VERY slow uploads

We are paying for 50/50 internet and are consistently getting 50/0.5. I have spoken to over a dozen tech reps and have had 3 FiOS visits to our home. This is getting rediclious and we are going to call again tomorrow. Here are our troubleshooting steps thus far:

1. Reboot
2. Unplug EVERYTHING from the Actiontec router except a single desktop & run speedtest (disabled WIFI too)
3. Installed new Actiontec router sent by Verizon
4. Tried 3 different computers each hardwired to the router w/ same lousy results
5. Cleared all cache, tried different browsers, tried multiple speedtest sites (Verizon, Speedtest.net, DslReports)
6. Tech installed new splitters & measured coax signal above -13dB
7. Tech installed new ONT outside
8. Tech tested PON connection
9. Tech tested speed at both the ONT & Router using his device
10. Tech completely bypassed coax and ran new ethernet from ONT to router WAN port
11. Tried bypassing Verizon DNS and used Google DNS (8.8.8.8 & 4.4.4.4)

The last few ones were today. On each of the last 2 visits, both the tech and myself wittnessed the upload speed reaching over 40mbps. Both times we cheered the problem was solved. Both times (and right now) the speed tests are sub 1mbps.

I tried uploading a 90MB file to Google Drive and confirmed that it was chugging along at 3mbps.

What else can we possibly do? We are getting fed up. Photo uploads to social media take forever. Websites sometimes stop responding. Verizon tech reps on phone are hit or miss. Everyone has a different solution. The 11 points above represent the cumulative knowledge of Verizon thus far.