The power levels are always in question but I believe gammas are equal to current blue evolution Vegeta and super Saiyan blue kaioken x 20 Goku. Now keep in mind I mean current Goku or after Moro arc wish this movie takes place so piccolo would have a pretty good estimate on how powerful all the Z fighters during the time of dragon Ball super hero. So if you're one of the people who don't believe the gammas are equal to ultra instinct or ultra ego I place them on par with super Saiyan blue kaioken x 20 Goku who himself is definitely more powerful then ultra instinct Goku during the tournament of power.
Side Note: this is not the entirely Superheroes arc. Pro Tips: read the manga, there one last battle to close Superheroes arc (that one last chapter before Akira Toriyama passing away)