FWIW as added comments: I have had the same two paralled 12V true deep cycle batteries in our RV for 8 years and they're still providing our drycamping power needs just fine.
However they are AGM and I have them connected together in a balanced configuration and with massive cabling to help ensure that they play together as one large battery. There is no way either of them can act differently from the other one - either during charging or during draw-downs.
These two 12V AGM batteries have even been connected in direct parallel with the wet acid engine starting battery this whole time whenever the main engine is running. The main engine battery is on it's 6th year.
