Is there someway to make "My maps" in google maps available offline with location markers?
It seems to me that you are talking about your "Starred locations" when you're talking about the markers layer on "My Maps", eih? These are stored in Google Bookmarks and can be exported -- including the locations.

As a general note: The way Googe has setup its Maps/Geo operations leads to a likely reality that Google will "never" provide good offline capabilities. Your proper solution comes from something that does. And that something is increasingly likely using OpenStreetMap. My personal recommendations for apps that can also (easily enough) handle your exported starred Google Maps locations are OsmAnd and Maverick. See OSM wiki for details and more options.