Canon EF 16-35 f2.8 vs Canon EF 16-35 f4 IS

Hello guys.

I’m a new Canon photographer. Building my own holy trinity and I arrived at the 16-35.

And I am deciding whether to buy the f2.8 version or the f4 version with IS.

i shoot mainly events like weddings, parties, clubs, all sort of low light situations.

But I also like to do astrophotography and landscapes. And architecture/real estate.

Now I know the answer appears to be obvious, but I specify I also have the 24-70 f2.8, that I use.

Given that, do you think I should still invest into the f2.8 or pair the 24-70 with the 16-35 f4 IS?

thanks in advance.