The nice think about RHEL/CentOS is, that their kernels have stable ABIs (kABI). That allows for third parties to provide binary kernel modules, and the OpenZFS

The nice think about RHEL/CentOS is, that their kernels have stable ABIs (kABI). That allows for third parties to provide binary kernel modules, and the OpenZFS project actually provides the kABI-kmod tracking repo, so you can have an installation without any developer tools installed (which I prefer). So the problem wasn't really with kernel modules, the problem was the integration with the system, and nobody really cared - the above mentioned issue is still open, 2 years later. Another nice thing about CentOS is, that it was supported for 10 years. Debian is supported only for 3. It tkaes 5 years for Synology to get a new release done, so they also do have kinda-long term support.