Strange hub performance via rPi

Strange issue today. I've set up an rPi for remote access via VNC while away. However today I noticed at the property that the response of the hub in the browser running on the RPi is incredibly slow whereas using my mobile phone to access the hub directly works fine. I don't understand this. Why would the hub seem to be hung when accessed from the RPi (whether via VNC or directly at my TV screen connected to the rPi at home) but perfectly ok when accessed from my mobile phone? Dashboards seem to be working fine. comes up fine. It's just the hub IP address that seems hung/incredibly slow when trying to access via the rPi. Other websites respond as expected. My brain hurts.

What model Pi is this? The chromium browser used in Raspbian is not the most powerful one out there. Remember, you're not dealing with a full PC here, it's just a Raspberry Pi. A lot of the resources are going into resolving the desktop. If you use your pi headless to create a VPN tunnel to the network, that will save a lot of the processing power. There's no separate GPU on the Pi so it all falls on the processor.

Thanks Ryan. It's a 3B but I have two set up for different properties. The one works fine. The other does not, but it's just the Hubitat IP that is slow. Google etc seem to work fine. It's very strange. I've rebooted the Pi and Hub multiple times, no difference. Will continue to explore what's going on.