This was requested by Choyfider, thanks for the suggestion

So I'm going to be honest here, I'm not a godzilla expert, I don't know all the different godzillas, I don't know the difference in power between these godzillas and the best showings from these characters are from fighting Godzilla and they all scale because they can all compete with Godzilla, therefore I'll just be assuming that Godzillas power goes constantly throughout the different versions therefore this may not be the most accurate conclusion. I also won't be going over speed, strength and so on because again there best showings are from Godzilla so I'd basically be saying for all three "he's this powerful cause he can take on godzilla"

Anyway let's begin with Space Godzilla

So space godzilla from what I've seen seems to scale to Godzilla the best, what I mean by this is the two of them seem to be the closest in power when it comes to comparing these monsters to Godzilla, if anything he may be weaker than Godzilla especially considering in their first fight Godzilla only lost cause he was protecting his child but without that limitation he does take out space Godzilla

Abilities

Superhuman Physical Characteristics, Flight, Aura, Energy Manipulation (Cosmic Energy, Electromagnetic Energy, Solar Energy), Crystal Manipulation, Regeneration (At least Low), Telekinesis, Forcefield, Can survive in the vacuum of space

In terms of King ghidorah in most showings he does indeed have the upper hand on Godzilla, sometimes Godzilla even needs help to survive, in Godzilla vs King ghidorah it was a stronger and larger godzilla that fought him and throughout most of the fight Ghidorah had the upper hand.

Abilities

Superhuman Physical Characteristics, Flight, Energy Manipulation(Energy Projection and Energy Absorption), Breath Attack, Gravity Manipulation, Air Manipulation | Same, with Electricity Manipulation | All the normal powers of King Ghidorah, Laser Triple Beam, Can fire anchors that electrocute his opponent, Forcefield Creation | Superhuman Physical Characteristics, Flight, Electricity Manipulation, Resurrection (Though this is non-combat applicable) | All powers from his previous form plus Forcefield Creation and Gravity Manipulation

Destroya didn't just fight Godzilla, he fought burning Godzilla, this Godzilla was becoming so powerful that his body couldn't control the power and was going to blow up, Destroya still seemed to compare pretty well however and may have been a lot stronger than Burning godzilla

Abilities

 Superhuman Physical Characteristics, Flight, Duplication, Shapeshifting, Regeneration (At least Low-Mid), Energy Manipulation (Energy Projectionand Energy Absorption), DNA Absorption, Micro-Oxygen Manipulation (Air Manipulation, Atomic Destruction, Durability Negation, Regeneration Nullification), Longevity, Prehensile tail

Conclusion

So this is a bit of a tricky one but first off I'm going to say that Space Godzilla loses, he is definitely the weakest here and would not defeat either of these two monsters, as for Ghidorah more than likely he is faster than Destroyah but Destroyah is more than likely stronger, Destroyah when he fought burning Godzilla used his mobility to get the upper hand while Ghidorah always fights godzilla head on, however due to the strength difference between burning godzilla and normal Godzilla I'm giving this one to Destroyah

Winner: destroyah