Hasn't it been implied that the DFs come from one's desire/imagination? Assuming Joyboy is from Elbaf and Nika was a God to them wouldn't it make sense that Joyboy would desire/imagine his powers?
Joyboy is from the Ancient Kingdom.
Nika is a symbol of god in Elbaph culturally the way Zeus is a god from Greek mytholoy.
When VP said theories, he meant people don't need to theorise about gods existing because when he told SHs Luffy was a god, they said he's an idiot and not a god. VP said they didn't have to theorise if gods exist. DFs do come from hope.
The desire of DFs is not about a specific person desiring a DF. if the world desires the fruit will exist. Anyone can come across the DF and eat. Eating it doesn't mean you wished for it, being able to acquire a DF just means people have desired that power.
Joyboy didn't imagine the power anymore than Luffy desired to be the Nika Nika no Mi user, or Brook desired being the revive revive user.
Buggy's the user of the Bara Bara no Mi and never wanted a DF, so Joyboy being the Nika Nika no Mi doesn't mean he desired it, he found it and ate it like everyone. Most people don't even know what power the DF they're eating does until the power manifests.
The AK was the birthplace of DFs, right?
That has never been stated, DFs come from desire. Not from the Ancient Kingdom.
I'm feeling that Raftel is the AK.
Definitely isn't because Dr. Clover told us the Ancient Kingdom was already destroyed. Laughtale also exists, so it definitely can't be the Ancient Kingdom.
Why wouldn't the WG government in 800 years actually find the RPs and go for themselves?
They can't find it which is why they banned people from studying Poneglyphs.
If people gather the 4 Road Poneglyphs, they'll get the coordinates to Laughtale which is where the entire documentation of the Void Century exists.
Since the WG can't gather the Road Poneglyphs to collect the Poneglyphs with the Void Century for themselves, they don't want anyone studying the Poneglyphs so they have no chance to find it.
Furthermore, this is why the WG like balance between Yonko, Shichibukai and WG. Big Mom had a Poneglyph, Kaido had one too... balance means no Emperor is defeated and everyone is holding on to 1 Poneglyph. If they're all holding Poneglyphs individually, then no one can put all the Road Poneglyphs together.