Running a command in a runtime based sandbox with an alternate .var/app/APP_NAME

1

If i need a quick shell in a sandboxed environment, I use something like this

flatpak run --sandbox --share=network ---persist=Downloads \
  -command=bash org.freedesktop.Sdk

So anything I download is present in ~/.var/app/org.freedesktop.Sdk/Downloads

Can I somehow configure flatpak run to use a custom subdirectory in ~/.var/app/?