You can’t think of panels as a voltage source like you can a battery. Their voltage and current and therefor power output fluctuates based on the load on the panel, how much sunlight it is exposed to, how evenly that sun is applied across the array (or singular panel for microinverters), and the panels temperature. MPPT (Maximum Power Point Tracking) controllers will sweep through the range of current draw to find the voltage/current combination that results in the maximum power (Watts) being produced. For a microinverter or grid tied string inverter that power is immediately converted to AC power that is pushed back into the grid (or an AC coupled inverter with batteries). For a solar charge controller that power is converted to a set voltage for charging the battery bank. If you have 2 MPPTs connected to the same panel in parallel they will not sync up. At best they will constantly sweep their range and arrive at the wrong power point to generate the most power from that panel. At worst one or both of them will give up the magic smoke.
A better option would be to split your array in half and purchase a hybrid inverter. The hybrid inverter would power your critical loads off the panels connected to it, battery, generator, or utility in whatever order you set in the settings. There are models of hybrid inverters that can grid tie and push power back to the utility just like your current grid tie does, and you would just set it to do that after the batteries are charged and loads connected directly to the inverter are satisfied. These inverters usually have an automatic transfer switch built into them, meaning if the power goes out it will automatically disconnect from the grid and continue to power the loads until solar and batteries are exhausted, and will reconnect to the grid when it comes back up. There are even some that can AC couple an existing grid tie inverter that meets UL1741SA and use those panels to power loads and charge the batteries.
There are ways to accomplish what you want to do, but running 2 inverters DC coupled off the same array of panels is not one of them.