So, there's some baggage in whether "revealed zones" is defined in rules text and whether a creature permanent can share a name with a card but let's assume that all works because you can always reword it.

If you have two of these revealed, they tap for one mana each. Not great. If you have three running around they're all sol rings (only the ones on the battlefield mind you). This creature cannot generate infinite mana unless you somehow get 6 copies of it revealed. And that doesn't win the game unless you then have something to use the colourless mana or the untaps with.

Outside of a vacuum, 4 mana is an expensive untap but it's flexible so maybe that's too strong? It's the same rate as Staff of domination so I feel it's not broken. Additionally I can imagine games that go long, you've had a few of these creatures die and sent to exile so the next one you play is tapping for 3 or 4 mana all by itself. Is that broken? I don't think so given that there are plenty of other dorks and rocks which can give you similar mana amounts. Like timeless lotus. It costs more than this but you've need to get to at least turn 5 before this could produce that much mana.

I actually think I like this card and wish it existed. It's a neat little win condition I could see myself building a deck around in brothers war standard or pioneer.