Identify all unique values in each row (dynamic data) and return the column header

Hi there Excel community,
Table1 here contains dynamic values that are updated all the time and are rounded to 0 decimals. I basically need to retrieve all the first instances of such values (those above 0) for each row: as shown in Table 2. I'm not sure how to do that other than thru INDEX & MATCH, and I'm assuming that the lookup values B20:L20 range from 1-10 (but in reality it can go above 10) I'm using the following formula in Q21: =INDEX($B$4:$AB$4,MATCH($Q$20,INDEX($B$5:$AB$16,MATCH(P21,$A$5:$A$16),))) but it's giving me wrong results. Why isn't it working correctly?
Better yet, is there a formula which can simply return all first instances (by date column header) of all unique values in each row (from Table1)? Thank you in advance for help.