another approach I've used for a similar problem...
Several releases ago, I fixed a Darwin/macOS package well enough to build and install it, but the patching was messy and not suitable for a maintainer request. I'm still using that fixup package because the build is still broken in the current release.
Since I installed it with the old tag in the LOCALBASE, I can still reference the bin file directly, and it still links the right libs, even though my current PATH points to the LOCALBASE of the current release, I'm only using one package in from the old install.
In your case you could bootstrap with LOCALBASE=/opt/pkg and make another bootstrap with LOCALBASE=/opt/2025Q1-radio just for the bootstrap and your fixup. Then build for and packin update /opt/pkg without disturbing the /opt/2025Q1-radio install.
I just wrote a guide that explains this for a very similar circumstance
Regards,
-George