I think that relation for Δήμος Κεφαλληνίας https://www.openstreetmap.org/relation/2211891 is no more valid. I think it was divided to 3 smaller municipalities in 2019 (https://el.wikipedia.org/wiki/%CE%94%CE%AE%CE%BC%CE%BF%CF%82_%CE%9A%CE%B5%CF%86%CE%B1%CE%BB%CE%BF%CE%BD%CE%B9%CE%AC%CF%82). But I’m not Greek and I don’t have local knowledge to put it correct. Could you adjust the admin_level=7 boundaries?
And I think that Δήμος Καλαμπάκας https://www.openstreetmap.org/relation/2238560 have name Δήμος Μετεώρων now. And maybe the wikidata should be changed to https://www.wikidata.org/wiki/Q15979847
Have a nice day,