But in 10 years nobody has built a low-cost design right? Since OP has open sourced the build and software, that may change now.
> In my case, the BOM was close to €2500, so be prepared for that.
EDIT: someone pointed out that there are actually some designs available on AliExpress, e.g. https://a.aliexpress.com/_EzMRNIv €250 for one axis (edge) and €500 for a 3-axis (single point).
Recently there was a post here about researchers training NN to fly a chepish very small drone. No messing with PID adjustment.