Your picture, which includes a USB/RS232 adaptor that you didn't mention in the text, looks like it would work fine (assuming that your "galvanic isolation" circuit works.) You'll need to do something to replace the DTR "auto-reset" functionality.
The "FTDI" would normally replace the USB/RS232 device, rather than the max232, which is why people are a bit confused.
You should be able to find an isolator that doesn't require the rs232 step (or make one yourself.) For example: https://www.amazon.com/KNACRO-Isolated-Serial-Module-Fully/dp/B07L2MT5QJ