DIAGNOSIS This is asymmetric performance. Common causes are: a bad Speedtest server selection, ISP congestion on upstream, or SQM (Optimize for Conferencing & Gaming) being enabled on a slow internet plan.
FIX First, disable eero Labs features that manage traffic. In the app, go to Discover > eero Labs. Turn OFF 'Optimize for Conferencing & Gaming'. Retest speeds with a wired connection to the gateway eero using a site like speedtest.net or fast.com.
IF THAT DIDN'T WORK Test directly connected to your modem to establish a baseline. If upload is still slow, the issue is with your ISP. If upload improves at the modem, the eero's SQM may be misconfigured. A network restart from the app (Settings > Troubleshooting > Restart Network) can clear residual SQM states.
HEADS UP SQM (Smart Queue Management) caps upload speeds to manage latency. On plans under 500 Mbps, it is beneficial for gaming. On faster plans, it can unnecessarily limit upload. Know your plan's provisioned upload speed.