According to the documentation the TTGO VGA32 1.2 comes with 520k not 320k, hence can run with 48k RAM not 20k RAM. Figure it out and see if it does actually work.
Problem is a lot of ESP32s only come with 320k , most in fact. AFAIK there is no way of discovering this in code so that the available RAM changes depending on the chip. Leave for now.
According to the documentation the TTGO VGA32 1.2 comes with 520k not 320k, hence can run with 48k RAM not 20k RAM. Figure it out and see if it does actually work.