To add to that, the public institutions in BG are in possession of a 0.5-0.3m/px orthophoto and a DEM with a similar resolution derived from it. This was acquired between 2016 and 2020 and entirely paid for with eurofunds.

You literally cannot get access to it, even if you want to pay let alone find it as an opendata dataset. Mind you, all military objects on it have been removed.