Okay, I think I understand. Is your question: “How do I find the user’s user id in a column in a Google Sheet and then update other column values in that same row?” If so, that’s essentially a vlookup and it’s been discussed before on the forums.
I have an example of how to find the matching row here: Thunkable and returns a corresponding value from my sheet - #2 by tatiang
Once you have the row number, you can just use the update value block to change values in that same row (row number = row id).