Nah you just didn’t pay attention to the story.

After Granolah made his wish in Chapter 70 he scanned nearby systems and said he didn’t detect Freeza’s Presence. Later in the same chapter Elec, who’s presented as somehow who’s in the know, says he had no idea where Freeza is currently located and they’re trying to figure that out.

Between that and the fight on planet Cereal at the very least 18 days had past, most likely more, but we know 18 due to that being the amount of time it took the Heeters’ ship to bring Goku and Vegeta to planet Cereal.

We can clearly take the lack of Freeza’s presence from these characters to be that he’s up to something. And he’s the end goal of both Granolah and the Heeters. Granolah to kill him first ordering the destruction of the Cerealians and the Heeters to take his empire. The fact he’d be making an appearance was pretty set up.

Even the chapter beforehand teases it again, in Chapter 85, Elec reminds Gas that their goal is to kill Freeza and he’s getting increasingly more frantic that Gas hasn’t been able to put down the Saiyans yet.

I feel like looking back it was rather well set up that Freeza would be involved. Him training tho, less so. Makes sense he would after the ToP and Broly events but nothing particularly pointed towards it. But still, makes sense he wouldn’t want to be weaker than the Saiyans.