Is there a way to update this even if it no longer gets updates?

Yes,. But... it involves rooting your phone, invalidating your warranty and installing a custom ROM, most folks don't do it As the song asks, "How bad do you want it?"

To learn more visit xda, if you decide to go for it look for what roms are available for your EXACT model. Read reviews and comments from users and be certain you understand and follow directions precisely. Before you do anything else backup everything and have the correct stock rom ready in case you need to restore it. I will link a helpful article below, you probably will not want 12. It isn't fully functional (yet). Be very careful a mistake can brick your phone. https://www.xda-developers.com/samsung-g...