Sign-up with https://www.appveyor.com ?
At least running an part of the tests would maybe help with windows regressions like:https://github.com/matomo-org/matomo/issues/11731https://github.com/matomo-org/matomo/issues/12290
But as far as I know only one job (not build) at the same time is free, so maybe only run on commits to 3.x-dev.
The free builds are queued up to run sequentially . If a project wants builds to complete sooner, they can upgrade to a plan for concurrent builds.