In the current Dragon Ball continuity of Dragon Ball Super, Frieza has undergone not one, but two immensely powerful transformations that have leveled up his strength to be comparable to that of a literal god. While that is impressive, Frieza already reached a god-tier power level way before his Dragon Ball Super transformations.
In the canonical film Dragon Ball Z: Resurrection ‘F’, Frieza is brought back to life following his devastating defeat to Goku on Planet Namek and his ultimate demise at the hands of Trunks thereafter. Frieza is resurrected by his former subordinates as they need him to get the Frieza Force back to be the feared army it once was. However, when Frieza returned to life, he was more interested in getting revenge on Goku for defeating him, but Frieza didn’t act hastily. Instead, Frieza trained for months—something he had never done before—and unlocked a form known as Golden Frieza which was relatively the same level of power that is harnessed through the god-like Super Saiyan Blue. Learning that even a small amount of time training can make him exponentially more powerful, Frieza later finds and trains in a pocket dimension similar to a hyperbolic time chamber and trains outside of time for ten years. By doing so, he unlocked a form known as Black Frieza which is evidently stronger than Ultra Instinct and Ultra Ego combined.
In Dragon Ball chapter 310 by Akira Toriyama, Goku and Frieza are in the middle of their iconic battle on Planet Namek, and it seems as though Frieza has the immediate advantage. No matter what attack Goku throws his way, Frieza just brushes it off or dodges it completely before answering back with devastating attacks of his own. While it seems like Goku doesn’t stand a chance, especially from the viewpoint of Gohan, Krillin, and Piccolo, Piccolo reassures the other two that Goku isn’t giving it his all and that this part of the fight is nothing more than a warmup. Piccolo even compares Goku’s new power to that of a god but also says that Frieza is wielding god-tier power as well.
One thing to keep in mind about Dragon Ball, especially the earlier chapters, is that the god-like power scale is not set in stone and varies greatly depending on the type of god one is talking about. Technically speaking, Goku surpassed the power of a god before the events of Dragon Ball Z when he fought and killed King Piccolo after training with Earth’s God, Kami. And before that, Goku surpassed Korin’s power, another god of Earth, when he was training to beat the deadly assassin Taopaipai. Most recently in relation to this chapter, Goku surpassed yet another god, King Kai, when he was training to fight the Saiyans who invaded Earth just a few chapters prior. So, while Frieza is clearly no match for a god like Lord Beerus in this chapter, the fact that he is stronger than Goku at that time–before the Saiyan unlocked Super Saiyan–means that he was more powerful than every god Goku surpassed prior to their fight.
Basically, being stronger than a god in the Dragon Ball universe sounds impressive, but it depends entirely on which level of god one is talking about. However, in this case, that is irrelevant as the argument here is whether Frieza achieved god-tier power before his most recent Dragon Ball transformations in Dragon Ball Super–and this chapter proves, without a shadow of a doubt, that he absolutely did.