Please be aware that enabling developer mode comes with permanent consequences for that install. There’s a reason why the official docs points out it’s unsupported.
Considering that, and your use case here, I would instead recommend that you put the binary on your pool somewhere, and that you append the relevant PATH in an rc-script. That will survive updates as long as the binary itself keeps working.
In the post you linked to, one of the suggestions you give is to remount a locked down directory as rw.
This is ill-advised for the reason I explained, among other things.
I presented an alternative that survives updates and doesn’t mess with the OS.