Wired connection upload speeds extremely slow. Please help.

I have an Xfinity XB8 gateway. On my home office PC, my WIFI speeds are around 700 Mbps download/350 Mbps upload utilizing the Ookla Speed Test. Over the wired ethernet connection via port 4, my speeds are around 1-2.3 Gbps download which is fantastic, but only 3 Mbps upload. I've tried several different Cat 6 and Cat 8 ethernet cables but the speeds are consistent. I've tried the 1 Gbps ports as well but the upload speed remains consistent at 3 Mbps. Any ideas what would be causing such slow upload speed readings over the wired connection? I tried several different online speed tests, and all of them gave similar results, with the exception of Measurementlab.net, which reported an upload speed of around 285 Mbps.

I have a Killer E3000 2.5 Gigabit Ethernet Controller and my WIFI connects via a Killer Wi-Fi 6 AX1650i 160MHz Wireless Network Adapter.

Update 1 - I uninstalled all the network adapter drivers and did a clean install with the latest drivers. Immediately I saw upload speeds via my wired connection around 300 Mbps on the Ookla speed test. Within 30 minutes my upload speeds were testing back down at 2-3 Mbps. I'm not sure why that would be or what else to do to try to resolve this issue.

Update 2 - I followed these instructions and my upload speeds are back up to around 285 Mbps. I will update this post if anything changes.

• Right-click the Start menu and select Device Manager.
• Expand Network adapters, right-click your Intel Ethernet Controller, and select Properties.
• Go to the Advanced tab.
• Locate Large Send Offload v2 (IPv4) and change its value to Disabled.
• Locate Large Send Offload v2 (IPv6) and change its value to Disabled.
• Locate TCP Checksum Offload (IPv4) and change its value to Disabled.
• Click OK and restart your computer.