Hi, and welcome to the plugin developers. You mentioned using a Linux build chain. @qno has done some excellent work on using GitHub to produce builds for all four supported architectures. Whenever you push to your repository, you can click on the Actions tab at the top of the GitHub repository and watch the builds complete for each system. Once these are completed you will see green indicators, scroll to the bottom of the page to find the plugin downloads that you can distribute for testing.
All you need to do is copy the file located at vcv-plugin-cmake-example/.github/workflows/build-plugin.yml at main · qno/vcv-plugin-cmake-example · GitHub to your repository, and push to github. This only needs to be done once and will work for all future commits. If you have any issues with this I am happy to help.
I have just tested this by forking your repository and can confirm your plugin builds and runs on all four platforms. If you would like to look at what changes I have made : GitHub - curlymorphic/SIM: VCV Rack Plugins . The example builds can be found : Added github build chain, based on work by qno https://github.com/qno… · curlymorphic/SIM@97d0f07 · GitHub