How do we get around the SSJ Future Trunks >= SSJ Namek Goku in the anime?

In the anime filler, King Kai implies Future Trunks is only a little stronger than Goku. However, Trunks still claims he can beat Mecha Freeza in seconds even at full power, although Goku had to struggle against 100% Freeza. How do we explain this if we want to include anime filler?

1. Goku didn't have access to his full SSJ power right away on Namek.
2. Trunks underestimated Freeza.
3. Trunks was just provoking Freeza; he wouldn't let him go full power.
4. Goku didn't fight Freeza seriously.
5. Other.

5. Kaio didn’t know the full extension of Trunks’ power OR he was talking about Yardrat Goku.

There’s no getting around it