From what I can observe, quite a lot, at least from the most popular ones, seem to have both. But something I notice is that, when it has a physical release, seldom the comics’ digital counterparts are sold in DRM free formats. And when it comes to digital-only comics, I would imagine that usually either their creators don’t have the resources, and/or the comics’ reach is too small to justify a physical release.
From what I can observe, quite a lot, at least from the most popular ones, seem to have both. But something I notice is that, when it has a physical release, seldom the comics’ digital counterparts are sold in DRM free formats. And when it comes to digital-only comics, I would imagine that usually either their creators don’t have the resources, and/or the comics’ reach is too small to justify a physical release.