You can specify in platformio.ini different data folders for each build environment
[platformio]
data_dir = ${PROJECT_DIR}/data-${PIOENV}
where $PIOENV resolves to the current build environment.
For [env:esp32dev], data_dir becomes data-esp32dev
and filesystem image is built in .pio/build/esp32dev/spiffs.bin
from files in data-esp32dev
For [env:esp32ota], data_dir becomes data-esp32ota
and filesystem image is built in .pio/build/esp32ota/spiffs.bin
from files in data-esp32ota