You may be referring to my example in my Concepts app. Had to take a look again to see how I have it set up, but I think what you are referring to is trying to create a relation from what looks like a relation, but is in fact an array column build from several individual columns. First of all, in my example, the Category 1, Category 2, Category 3 columns may look like a relation because of the icon, but they are actually an array column. That’s why they were sequentially numbered. It looks like you took those numbered columns and gave them individual names instead, which no longer joins them together as an array column and that’s why you see your individual Category columns instead. I’m guessing you are trying to link all of your Category columns as one joined column array to another sheet in your relation? In the concepts example, the numbering is very important for creating the array column to perform the relation. Array columns are multiple columns that have the same name, but are sequentially number, so they are joined together as a single array column.
Again to clarify, array columns and relations are very different things, but for some reason, they share the same column icon. An array column is not a relation and a relation cannot use another relation as part of it’s link. You can however use a lookup column from another relation as part of the link in a new relation, but that’s unrelated to your question for now.
If you are looking for another example of a multiple match filter, I would suggest taking a look at this post: