To go full circle and solve the issue... Are you using platformio rather than arduino?
You need to add:
# Name, Type, SubType, Offset, Size, Flags
nvs, data, nvs, 0x9000, 0x5000,
otadata, data, ota, 0xe000, 0x2000,
app0, app, ota_0, 0x10000, 0x640000,
app1, app, ota_1, 0x650000,0x640000,
spiffs, data, spiffs, 0xc90000,0x370000,
in a new file "default_16MB.csv" in the same folder as platformio.ini, and modify platformio.ini to add:
board_build.partitions = default_16MB.csv
build_flags =
-DCORE_DEBUG_LEVEL=4
-DBOARD_HAS_PSRAM
-mfix-esp32-psram-cache-issue
Which fixes the RAM issue and allows using the full size canvas.