I found two in the southeast part of Paldea, but I have no idea what they're for.

Not what I was asking.

None in the crater. If you know where the shrines are located, the stakes are generally around those regions of the map. There are fairly large gaps between the “territories” of each color

Yeah, there's a story bit at the school that explains they're all in the same general vicinity. I saw that much. I just rather finish as many side quests as I can before beating the game, rather than waiting until after, so I'm trying to wrap this up before moving on to the main story finales.

Ign has a guide that can help find them

I don't want a guide. That completely defeats the whole point of them even being hidden in the first place. I just wanted to know if I'd be wasting my time trying to do it before heading to the Great Crater.

No, if you do the history teacher's bond events she marks the locations of the shrines on your map and all the stakes are within the same region as each shrine, and none of the shrines are in the crater.

Yes, I've done that event, but you never know. I was thinking it was possible they could've put one of each stake in the crater as sort of a way to try and force that quest into the post game, which is why I wanted to make sure. Especially since it would make sense from a story perspective to put one stake from each shrine in the most inaccessible place possible. Better to just check, than spend a dozen hours looking only to then find out it was a fruitless effort.

Iirc they said that the stakes had a certain range, as the reasoning for why they were all in the same region as the shrines, and the shrines are all towards the edges of the region away from the crater

Indeed, but they had to have chosen where the shrines would be placed. Either way, whether or not it makes sense from a story perspective, forcing it to be post game content seems like something that would be done from a gameplay perspective. Like have one stake at each of the farthest corners of the crater, as if sitting at the very edge of their range.

Nope. None them are in Area Zero. I've completed my Pokedex on Scarlet too.