In my experience, the hardest part of developing with eBPF is dealing with the multiple kernel versions and configurations that the target machines may have. It's a challenge not only because eBPF features were added gradually but because the internal data structures are not stable. While CO-RE finally makes it possible to be offset agnostic and allows for dealing with things like missing struct members, it's still very much a game of finding out when the code is deployed in the wild. Unit testing is important but I long for a way to easily test across a large matrix of kernel versions/configs (here at EdgeBit, we would be happy to pay for such a service).