Filter but with Array Condition?

Hello,

I have two sets of data that changes from week to week, with IDs & Dates. I'm trying to create a dynamic table that counts how many unique calendar days are associated with each ID.

Date table has Ids & Dates (ID in col 1, Date in col 2) - it's an array starting in A4

ID table has IDs for the week to be needed (Just an array of IDs that's on T4)

I came up with Count(unique(filter(choosecols(A4#,2),choosecols(A4#,1)=T4#))), but that doesn't work because T4# can't be an array. It works with T4, but how can I dynamically put it on every row?