If interface speed cannot be defined, it gets 10 Mbit/s, which is too low for the default value nowadays.
WARNING: Interface speed cannot be determined (assuming 10 Mbit/s)
We probably should increase the default speed to at least 100 Mbit or 1 Gbit
https://github.com/vyos/vyos-1x/blob/c07f27e8e23255cc970fa86f6a97c1bdccbcdbd8/python/vyos/qos/base.py#L169-L176