In response to a request in another thread, I have made a build of IodéOS 5.1 for this device.
It’s available from sourceforge
https://sourceforge.net/projects/pf-custom-roms/files/DRG/iode-os/
I do not own one of these devices so…
THIS BUILD HAS NOT BEEN TESTED AT ALL - USE IT ENTIRELY AT YOUR OWN RISK!
It should be possible to install the build by following the instructions for installing LineageOS
https://wiki.lineageos.org/devices/DRG/install