It was Talbot enhanced with Daisy's powers in the original timeline.
In both timelines, the team spends its resources on the Centipede serum for Coulson to use. In the destroyed world timeline, he either uses it, or otherwise doesn't hand it to Daisy, according to future Yo-Yo (Episode 5.10, Past Life). It's that secret handoff of the serum from Coulson to Daisy that ultimately breaks the loop.
During the finale, the same events Deke showed to Daisy back in the future (Episode 5.02, Orientation Part Two) are shown again to the viewers, with Daisy getting off the Quinjet and looking back to speak to its occupants, before rushing off to battle in the evacuated Chicago (the show even treats us to the same distant camera shot used in the newsreel). The timeline at this point is thus the same as the original for everyone except Coulson, who has handed off the serum.
In this original timeline, Talbot would successfully absorb Daisy, incorporating her powerset to more quickly mine the planet for Gravitonium, which ultimately triggered the 12.8 quake that would eventually destroy the planet. Neither of them individually are capable of breaking apart the planet, but by their powers combined, they are Captain Destructo-Planet, Destroyer of Worlds.