In the tournament of power, when Freezer faced Cabba, Cabba turned into SSJ2 and Freezer who was in 4th form transformed into Golden Freezer and defeated Cabba SSJ2 easily. I thought Freezer 4th form was strong enough to defeat Cabba SSJ2 but him transforming into Golden Freezer make it dubious. Can Freezer 4th form defeat SSJ2 Cabba?
No. If you recall, Back in the ROF arc, Base Goku was easily overwhelming Final Form Frieza. Since the Golden Frieza multiplier is > Super Saiyan Blue, Frieza had the advantage.
Frieza stated that he mastered the transformation and stopped the stamina issue with the Golden Form before the T.O.P. He never necessarily had an opportunity to train.
The Universe 6 Saiyans are very comparable to the Universe 7 Saiyans. Cabba was capable of holding his own against a Base Vegeta in his Base form. Even in Case of Caulifla, she was holding her own against SSJ, SSJ2 Goku etc. While the latter is stronger, Cabba isn't far off. Since SSJ2 is 100 * Cabba Base, Final form Frieza wouldn't stand a chance(This is because of how strong base Cabba is). Hence, he had to turn Golden to quickly finish the fight.