Legacy Update, how to uninstall MAC

I own a MacBook Air early 2015 and I didn't think twice when I downloaded the legacy edition.

I've read that I don't need this patch but since I've updated it already I am only experiencing problems with the game, like weird glitches in my screen appear when im in build mode and my online things were also missing.

but now I've also read that I don't need the update and that I now kind of ruined the game since im not able to buy university since the legacy update blocks further DLC's.

I've already updated to Catalina and repaired the game but I still have the legacy installed. 

How do i delete the legacy update so I can buy the new DLC's??????

My Macbook's specs are:

MacBook Air (13-inch, Early 2015)

Processor: 1.6 GHz Dual-Core Intel Core i5

Memory: 8GB 1600MHz DDR3

Graphics card: Intel HD Graphics 6000 1536MB

please help me.