i.e, did the Norse Paganism the way the Swedes practiced it differ from the way the Danes practiced it, how the Norwegians practiced it, or how the Icelanders practiced it? If so, how did it differ? I am somewhat familiar with differences between the Norse religion and other Germanic religions, this question specifically focuses on Scandinavia and Iceland.
The TL;DR of the whole thing is we have no actual idea.
The sources which we have that depict pagan practice are either written by Christians (Vita Anskarii, Gesta Hammaburgensis ecclesiae pontificum, the Eddas, etc.) or don't describe worship directly (skaldic verse, the Merseberg charms, etc.) Archaeology can tell us a bit about major cultic sites like Uppsala, but the day-to-day is basically up in the air.
That said, though, it's very likely that regional differences in worship existed, just as regional preferences in deities were a thing.