That looks a lot better. A bufferbloat grade of C without SQM is nothing out of the ordinary.
- Do you get a steady 400mbit with the ISP provided router? The download result could be better, but that might be congestion on the ISP side of things.
- Could you please post the output of
cat /etc/config/network
- And the output of
ifconfig
to double check that you indeed have a public IP associated to your WAN port (ie, the modem is properly bridged). - Unless you have a good reason to use snapshot images, I would suggest sticking with the stable release for now. You can always start tinkering once the basic setup is working properly. Stable images for your router can be found here: https://downloads.lede-project.org/releases/17.01.4/targets/ipq806x/generic/
Make sure you use the sysupgrade image (since you are upgrading from lede to lede) and untick the keep settings
checkbox.