Got the address search in PM working again (without debugging via IDE) - here's what I did:

• connected device via USB with developer mode on
• opened a remote shell (within IDE)
• started "harbour-osmscout-server" via remote shell and PM on device
• (when trying to search for an address in PM) terminal output of started OSMSS told me: "ERR Error loading transliteration module, dir=/run/media/nemo/[sdcard-ID}/Maps.OSM/postal/global-v1/transliteration/transliteration.dat
  at libpostal_setup_datadir (libpostal.c:266) errno: None"
• made a backup of "transliteration.dat" and deleted the original file
• closed OSMSS in terminal and restarted it again
• OSMSS's map manager told me "Missing data: Adress parsing language support (106,527,869 [sic!])", downloaded this by clicking "start download"
• yeah, address search in PM is working again...

BTW: when starting OSMSS via shell I get

"library "/vendor/lib/egl/libGLESv2S3D_adreno.so" not found"

as well as

"[W] unknown:57 - file:///usr/share/harbour-osmscout-server/qml/platform/PagePL.qml:57:9: QML Loader: Binding loop detected for property "active""

(but seem no negative effect)