Are you using Pipelines in either github or another upstream source management platform? I don't know if they have a free build plan or not, but you can have an entire pipeline that just spits out an executable for one or more platforms every time you commit to your main branch, depending on how you have compilation set up (you can have it use both a Linux and a Windows VM for different steps in the pipeline too). It can even handle publishing them to a website if youre handy with bash and/or powershell scripts (or python or JS or whatever you can call from the pipeline).

I use the Azure DevOps version at work and its amazingly useful, but very confusing to learn at first.