In the latest Tech Talk the trunas devs are talking about spindown again:
Q3: SMART errors and drive spindown for spares
The statement here is that “we are welcome to hack it into working” but it is “not something they consider (to support?)” and that “it is not best practice”.
I don’t know if we can expect it to get fixed. Apparently it is at least not important enough to get in 25.10.1.
I think in the long run we can either choose to use the patch presented in this thread or to look for alternatives. Personally I’m thinking of switching to openmediavault. You can often read that it’s worse than unraid or trunas but I don’t really know why. With the plugins it seems like a really powerful system with the stability of Debian and support for ZFS and plenty of other filesystems. The dev also seems to have a lot of experience as a former freenas dev.