I don't know where to put, so I place this issue here.
OpenPlotter 4 uses network manger. The hotspot configuration lacks the settings
802-11-wireless-security.proto
802-11-wireless-security.pairwise
802-11-wireless-security.group
This seems to prevent devices like an EPS32 from connection to the hotspot. After setting
802-11-wireless-security.proto: rsn
802-11-wireless-security.pairwise: ccmp
802-11-wireless-security.group: ccmp
with sudo nmcli connection edit hotspot is does work.
The GUI connection editor does revert these settings (sets them to undefined).