Hello @forggi ,

Welcome to our community.

According to Google Translate, you are experiencing slow Wi-Fi speeds with the AX55. If there is any discrepancy, please describe it in English.

Regarding the warm router:
It is normal for TP-Link routers to feel warm during operation. However, since your router is placed on the second floor directly under the roof where ambient temperatures can get quite high, this is worth paying attention to. TP-Link routers are tested to operate reliably in room temperatures up to 40°C (104°F), but if the surrounding environment exceeds this, it could potentially affect performance. Here are some placement tips:
• Make sure the router is in an open area and not inside a cabinet or enclosed space.
• Do not place it on paper, cloth, or surfaces that block heat dissipation underneath.
• Keep it away from direct heat sources and avoid stacking it on top of other electronics.

If the ambient temperature under the roof is very high, consider relocating the router to a cooler spot to rule out heat as a contributing factor.

Regarding the slow Wi-Fi speeds:
Since you've already tried changing channels, channel widths, and performing a factory reset, here are a few additional steps that may not have been covered yet:

1. Log into the web interface, go to Advanced > QoS, and make sure QoS is disabled.
2. Open the Tether app, go to Parental Control, and ensure no parental control profiles are configured.
3. Go to Advanced > NAT Forwarding > UPnP and disable UPnP. Also, go to Advanced > Security and disable SIP ALG, as these features can affect Wi-Fi performance.
4. When running speed tests, make sure you're testing on the 5GHz network with your device placed right next to the router. Also try selecting different servers on Speedtest.net, as some servers may yield better results.

Best Regards.