Remove/overwrite default source tarball assets

My problem is that I have a repo which acts as a super-project of multiple other repos which really all comprise one project but have not converged to being a monorepo (and likely never will). The super-project uses git submodules to fetch the other repos (this is what submodules was meant for), but when I do a release, the default Source code (.zip) and Source code (.tar.gz) archives are missing the submodules. I can create better, “potentially even trimmed” source tarballs from CI where I can control which submodule to clone, how, etc. However neither can I remove these default assets from CI or via the REST API (they aren’t even listed as assets of the release), neither can I overwrite them.

What are my options to help my users not download faulty source tarballs missing crucial components of my project?