Having noticed the frequent ‘constant update’ where ddns interferes with pkgupdate ( either pkgupdate isn’t running but the rotating icon suggests it is or it is running but hung ) I manually ran pkgupdate. It gave:
https://repo.turris.cz/omnia/packages/turrispackages/Packages.gz is missing.
A manual wget of the file shows the same, just without the long time out and burning 100% of one cpu core.