First of all, your FK ID Categoria column is a basic text column. Unless your relation finds an exact match in your related table (another column that also contains to ID’s separated by a comma), then it is not going to find anything. Instead you need to use a Split Text column to split the comma separated list of ID’s into an array. Then use that array in you relation column. That way the relation can properly check each individual ID to see if there is a match.
In summary, create a Split Text column and use that in your relation.
If you intend to use a Lookup in a Title component, then it does need to be from a single relation (multiple unchecked). Although, I’m not sure how you intend to have multiple ID’s return multiple matching rows with multiple Lookups and display that in a Title component that’s capable of displaying only a single value.