Freeza was introduced as a being with 530,000 units of power. Obviously nobody should be ready to face him at the point the fight against him started. Instead of magically increasing everybody's power, AT should have delayed the fight somehow and make the group's powers increase in a more plausible manner.
For example, when they sense Freeza approaching, they ride the ship and go to another planet to hide. Then a few weeks or months pass before Freeza finds them. During that time, they all train. That explains the following increases:
-Vegeta: From 60k to 500k
-Gohan-Krillin: From around 25k to hundreds of thousands
-Goku: From 90k to millions
Goku could isolate himself somewhere to train alone and it takes him some time to rejoin the group, so there is time for the others to fight as in canon and Freeza to transform all the way to his final form.
For example, when they sense Freeza approaching, they ride the ship and go to another planet to hide. Then a few weeks or months pass before Freeza finds them. During that time, they all train. That explains the following increases:
-Vegeta: From 60k to 500k
-Gohan-Krillin: From around 25k to hundreds of thousands
-Goku: From 90k to millions
Goku could isolate himself somewhere to train alone and it takes him some time to rejoin the group, so there is time for the others to fight as in canon and Freeza to transform all the way to his final form.