Despite being called the Trinary Solar System, they do use universe here, but would have taken time to finish, so not sure how much above SS level it would be for destroying the Pas Q Machine at the end of Final
It's fairly varied.
Due to many characters being glass cannons you could more or less send humans against them. Some hit harder but physically many are just human.
People like Junko Hokaze or Kinuhata Saiai, who count towards the stronger regular espers, are just wall level.
There are a bunch of normal espers that can hit harder than that, but that are just glass cannons.
Above that are like City Block to triple-digit megaton magicians. Then some saint level fighters in the gigatons, I think.
And lastly we have a bunch of high-tiers in the planet level realm.
There are some characters in-between but it's more or less that, unless I have forgotten something. Of course many of the fighters are rather slow, so speedblitz happen easily.
A better matchup would be Betterman Cataphract Terra and his flower that sends niggas into an alternate dimension along with all the other crazy shit the Bettermen comprising his form can do cause Genesic Gaogaigar has no hax, only unga and that sadly isn't quite enough against jewaru.
I read the ending/final chapter to get to the juiciest bit: For all of Betterman Cataphract's Hax, it still barely managed to eke out a win against the pure unga and speed of Final Gaogaigar. They could've been much meaner to Final GGG given that Betterman Lume AKA discount Magneto is part of it but...
The Bettermen weren't exactly trying to completely destroy Gaogaigar or kill Gai.
The Pas Q Machine/Pisa Sol was draining the current universe of all dark matter to restore the Trinary Solar System's universe, although it took about a year, so at minimum it's multi-galaxy level, if not universal. Betterman Lamia sent the GGG all the courage of Earth to help empower them during their fight against the 11 Planetary Masters. Zonuda Robo's tech readout said she had infinite power as all of GaoGaiGar's methods failed against her. GaoGaiGar vs Betterman also has GaoGaiGar using the G-Stone and J-Stone to push back Triple Zero's power, which was equal to the Big Bang (which also goes along with the Z-Master being said to be a threat to the universe).