Refra Gallery is licensed as Apache 2.0, which is a permissive license GrapheneOS can bundle in the OS.
We use GPLv2 and permissive licensing for GrapheneOS to avoid more restrictive licensing than the AOSP. We'll happily use GPLv3 and AGPLv3 for components outside of GrapheneOS if we think it's the best fit for specific projects. We aren't currently licensing anything as GPLv3/AGPLv3 but we aren't strictly opposed to it outside of the OS.
We'll use what we think are the best open source licenses for what we want to achieve. What we want to achieve is usually broad adoption of our code with painless usage of it. That means we usually choose permissive licenses. We use GPLv2 in certain cases such as Vanadium where we decided we wanted extensions to our code to be under a compatible open source license instead of a source available license or GPLv3.
Ubuntu does not aim to be a permissively-licensed system. It can include copyleft (e.g. GPL) and permissive (e.g. MIT) without issue.
Permissively-licensed systems like FreeBSD and GrapheneOS cannot include GPL code if they want to remain permissive.
We do need to be careful with GPLv2 due to license incompatibilities. For example, GPLv2-only licensing such as the Linux kernel is incompatible with Apache 2 and GPLv3. GPLv3 is compatible with Apache 2 so GPLv2-or-later can be compatible but only by using it as GPLv3 with the extra restrictions too.
I guess it will make your life much easier if you wouldn't have to restrict yourself that much.
In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.
There are some cases where a separate work can be considered derivative and thus the GPL can apply. E.g. I think it is generally accepted that a program linked statically against a GPL library is considered a derivative work (and must thus must have a license compatible with the GPL). More controversial is whether dynamic linking creates a derivative work. To cover the latter case, a lot of copyleft libraries are licensed under the LGPL or the GPL with a dynamic linking exception.
At any rate, shipping a Linux distribution with GPLv2 code (e.g. the Linux kernel) and a GUI application that is under the Apache v2 license is not a problem at all (as long as the GUI application is not a derivative of a GPLv2 work).
(IANAL of course, so this is not legal advice.)
A compilation of a covered work with other separate and independent works, which are not by their nature extensions of the covered work, and which are not combined with it such as to form a larger program, in or on a volume of a storage or distribution medium, is called an “aggregate” if the compilation and its resulting copyright are not used to limit the access or legal rights of the compilation's users beyond what the individual works permit. Inclusion of a covered work in an aggregate does not cause this License to apply to the other parts of the aggregate.
If you'd include a GPLv3 gallery app in, say, a mobile OS, it does not mean that the rest of the OS has to be under the GPLv3. It merely means that you cannot limit the user's right when it comes to the GPLv3-part (the gallery app). They would still be allowed to redistribute/modify it and you have to provide the source code on request.
You only have to make other code GPLv3 if you somehow create a derivative work (e.g. linking against a GPLv3 library).
(IANAL blah blah)