[Bloat] speedtest-cli on multihomed gateway

[Kenneth Porter <shiva@sewingwitch.com>]

I'm trying to get my head around how to run speedtest-cli on a Rocky 8
box (RHEL8 respin) with LAN and three WAN connections. I want to run
speedtest-cli on all the WAN links to test each, and run the tests
from a timer to watch the speeds throughout the day (eg. a symlink to
a test script in /etc/cron.hourly or a systemd timer unit).
speedtest-cli accepts a --source option but it wants to always route
through the WAN link set to the default route when I specify the
addresses of the other two. From googling around it looks like I want
to run it in a "network namespace" but I haven't figured out how to
make that work.

I found this stackexchange answer on the namespace basics but I think
I need a few more commands to actually make an app usable in the
namespace by ifup'ing the interface, routing, and DNS.

https://unix.stackexchange.com/questions/234583/routing-on-per-application-basis

Hardware setup:

eno1: LAN, 10.96.0.64, default route for LAN
eno2: WAN1, 172.24.96.xxx, to ATT fiber gateway at 172.24.96.1
eno3: WAN2, 172.24.69.xxx, to Xfinity gateway at 172.24.69.1
eno4: WAN3, 172.24.0.xxx, to Xfinity gateway at 172.24.0.1

What I'm trying:

# ip netns add comcast-1
# ip link set eno4 netns comcast-1
# ip netns exec comcast-1 speedtest-cli
Retrieving speedtest.net configuration...
Cannot retrieve speedtest configuration
ERROR: <urlopen error [Errno -2] Name or service not known>

At this point I'm not sure what I need to do to make the network
namespace usable.