As the ticket you cite says, support for modules was dropped long before 2025.1.
You shouldn’t need to explicitly specify this. Use the SonarScanner flavor that’s appropriate to your build technology, and this should be handled for you automatically.
According to the docs, the GCov parameter is looking for a single path to a directory. So I suppose you’ll need to put them all in one directory, and then make sure the paths in those reports match up to what analysis is seeing. From a practical standpoint, it probably means making sure the file paths in the reports are all relative from project root.