Today (2020/12/20) Garmin Express (build 7.2.2.0) started to install a map update for my 'Routable Cycle map of Europe'.
However, the installation could not be completed because the Edge 1030+ (FW build 4.00) would not have enough 'free space' although I have only the 'Routable Cycle map of Europe' installed and no other map.
Garmin Express suggested to delete any IQ App but that did not make the update pass.
So, I relocated all *.gma and *.img located in the 'Garmin-map' on my Edge 1030+ to my PC (also as back-up) freeing about 9 Gb on the Edge 1030+.
Garmin Express was now able to install the latest 'Routable Cycle map of Europe'.
Not a friendly work around but for me it did the job.