Inverter 1500/2000? Many coffee makers are over 1500, most RV microwaves are over 1500.
I like my GoPower inverters.
GP-ISW2000 $600Generally I prefer separate components. So separate transfer switch and separate charging system. You can use solar and the existing converter for charging.
Solar components should start with the panels. Best deal is some local surplus of 30 volt home panels. You will need to find what fits. Look for 50 cents per watt. Get matching panels only.
Once you have the panels located then focus on the appropriate controller. This Project may go north of $1,500 by the time all is installed.