You might be pleasantly surprised with the migration process of issues -- I had some inlined images and checklists in Github that got seamlessly migrated to Git

You might be pleasantly surprised with the migration process of issues -- I had some inlined images and checklists in Github that got seamlessly migrated to Gitlab. I was pretty happy with how well it worked. This is just in terms of ripping off the band-aid. I'm not sure of any mirroring, but I don't think that would be worth the hassle.