Thank you for your response and for clarifying. I wonder if the defeat of Charles in the battle against the Danes will not cause a civil war among the Obodrites between the pro-Franco faction and the rest. Some chiefs might have tried to pass under Danes sovereignty and practically annexing part of the lands to the Danish state. Besides it would be nice to see what would come out of syncretism which and the Slavic and Nordic faith.
And while mentioning Slavs, we should also notice that Slavs were also present in southeastern part of Charlemagne's state and the death of Charlemagne at that stage means:
a) Carantania probably becomes independent again under native princes, since they lost independence in 828 for supporting
https://pl.wikipedia.org/wiki/Powstanie_Ljudevita (the Wiki article about that uprising is only in Polish, Croatian and Russian so OP
@Zillian would need to use Google Translate in reading about it)
b) There is no one to stop Slavic re-settlement in Pannonia (Slavs took it over after Avars got yeeted and Charles stopped them), so Pannonia will most likely end up more Slavic than IOTL, there might even be some state formed (IOTL, according to Czech medievist Dusan Trestik, Ljudevit, duke of Lower Pannonia was close to forming lasting state there, so if Franks are removed from picture it's likely he'd achieve that)
c) primary cultural influence on rising Slavic states (TTL Great Moravia for example) would be still Avar, not Frankish
So the whole central Europe would be much more Slavic ITTL with Elbean, Carantanian and Pannonian Slavs presumably surviving (with much higher population of Pannonian Slavs due to lack of Franks stopping settlement even if Hungarians will still invade, they'd most likely get assimilated Bulgar-style)
Responding to
@CommonwealthVictory 's post, civil war among Obodrites would be good information to tribe of Polans, as Obodrites were their enemies.
As far as syncretism between Slavic and Nordic faith goes, it's not very likely as Polabians had the most developed paganism among Slavs, in fact most of that what we know about Slavic faith comes from sources about Polabians.
But some residual Nordic influences might be thrown in.