I recently subscribed to a fiber connection (400Mbps parallel) [Converge in the Philippines]. I'm wondering if my Decos are malfunctioning after a firmware update or is it with my ISP. 

On the main Deco, I don't have problems - using speedtest.net on a laptop with Wifi 6 and a Galaxy 20+, I get around 380Mbps (up/down).

But when I move to a location where I connect to a slave Deco unit, my speedtest results significantly decrease to 100Mpbs (up/down).

Is this expected for a Deco X20 system?

Just for illustration here's my network


Internet > Huawei Echolife EG8145V5 (bridge mode) > Main Deco (wireless router mode) <> 2nd Deco <> 3rd Deco

- UPNP is off