With the notable difference that there is no magic ingredient to Overleaf. If you have all the files you can recreate the documents with a local latex installa

With the notable difference that there is no magic ingredient to Overleaf. If you have all the files you can recreate the documents with a local latex installation. Overleaf makes this easy, since you can sync it with github repos. Good luck accessing/recreating a google docs document if google has an unexpected downtime or gets shut down eventually.