There seem to be no way to create vxlan netdev with noudpcsum attribute. Adding a vxlan link with UDPCSum: false has no effect as the attribute is passed only when its value is true. So the attribute is set to whatever is the default for OS, which happens to be true on Ubuntu 22.04 5.19.0-46-generic (relevant patch), making it impossible to opt out on link creation.

Unsetting this attribute for existing netdevs isn't supported either:

$ sudo ip link set vxlan1 type vxlan noudpcsum
Error: Cannot change UDP_CSUM flag.

so LinkModify also expectedly fails.

What would be the best way around this issue?