No, Ultra Ego Vegeta cannot beat Black Frieza.
Black Frieza easily overpowered both Ultra Instinct Goku and Ultra Ego Vegeta in their initial encounter. He defeated both Saiyans with a single blow, demonstrating a significantly higher power level than either of them. Vegeta's Ultra Ego form, while powerful, was simply not enough to contend with Frieza's immense strength. Other fighters like Gohan Beast or Broly would present a greater challenge to Black Frieza based on current power levels.
