Hello @Hannah_Krumholz!
As @Christiaan_Huizer noted, you could change the lookup to a Filter() as it gives you more flexibility.
But you don’t really need a lookup nor a Filter formula in your case, as in the Column 1 you are pulling the Companies rows directly so you can get the Contacts directly from the Company Row as it follows:
[Column 1].Contacts.ListCombine()