Limits Network config

Host: Ubuntu 20.04
Kernel: 5.4.0-166-generic #183-Ubuntu SMP x86_64
Incus: v0.2
Bridged network

Config parsing error: Unknown configuration key: limits.priority
Config parsing error: Unknown configuration key: limits.max
Config parsing error: Unknown configuration key: limits.ingress

Is it due to Kernel not supporting?

Those are network device config keys, you need to apply them through to the nic device on your instance, not on the network.