I agree @DasRoteSkelett, it’s hard to avoid OpenEmbedded/Yocto (or buildroot, though I’m personally more in favour of OE/Yocto) for production.
Though there’re some building products on top of Ubuntu, in my experience, when creating a product, Yocto is typically the path forward which allows you for those customizations you mention above, and many more including additional security or leveraging a hypervisor. Within this last bit, you can actually create various VMs, each with its own rootfs. You can still leverage the Ubuntu rootfs in one such VM, but building such partitions requires you to step aside from the Ubuntu experience.
We wrote about this not long ago at ROS 2 Humble with Yocto and PetaLinux.
I share the feeling 
, but our group cares (the same group behind ROBOTCORE® and the RPU) and is the one behind the effort bringing Yocto support for Humble (see Humble release thread, see Humble support in Yocto (Honister)). By the way, ROBOTCORE® (product, see tech specs) offers Yocto support and Acceleration Robotics offers consulting services around Yocto as well.
Community contributions-wise, I actually updated the recipes a few weeks ago over the summer (see open PR).
I also volunteered in the past to take over maintenance of meta-ros but never heard back from anyone. Let me reach out again to @tfoote and @Katherine_Scott to see if we address this.