I would not provide precompiled binaries for other systems if I could not even test it properly (nor know all of the details for programming for those other systems), whether or not it uses GitHub Actions.
If you do use GitHub Actions for compiling, then it might be better for the actual implementation of compiling to be in a separate file (which can also be used outside of GitHub) and the GitHub Actions file will only specify the conditions to trigger that separate file.
(I do use GitHub Actions, but only to automatically assign issues to myself (which is not something that is necessary in order to work the software that is being made by your repository). If it is moved to (or copied or mirrored to) something else that cannot use GitHub Actions files, it might have another way to auto-assign issues or make it unnecessary to do s.)
If you do use GitHub Actions for compiling, then it might be better for the actual implementation of compiling to be in a separate file (which can also be used outside of GitHub) and the GitHub Actions file will only specify the conditions to trigger that separate file.
(I do use GitHub Actions, but only to automatically assign issues to myself (which is not something that is necessary in order to work the software that is being made by your repository). If it is moved to (or copied or mirrored to) something else that cannot use GitHub Actions files, it might have another way to auto-assign issues or make it unnecessary to do s.)