Maybe consider the use of FILTER():

=FILTER(DATA!A:AF, B1&C1&E1=DATA!AA:AA&DATA!AD:AD&DATA!AC:AC)

I myself would not approach things the way you are doing in this sheet. (I always recommend using a separate sheet within your destination spreadsheet where IMPORTRANGE brings in all of the data from the source location, and then using that single sheet in the destination spreadsheet as the reference for all other formulas, such as the ones you're trying to use.)

In addition, your sheets are inaccessible (i.e., "Comment only"). So neither I nor anyone else would be able to setup an alternative method for you to consider.

That said, and working with what you do have, here is how you might adjust the B36 formula...

Here is the formula you originally wrote (and which is not working):

=INDEX(importrange("https://docs.google.com/spreadsheets/d/1mAssNMTGXcMcuYhjDWq6lNfWOdgUfI6FbGSWushGAMg/edit#gid=0",$J$1&"!A4:H26"),MATCH($A36,index(importrange("https://docs.google.com/spreadsheets/d/1mAssNMTGXcMcuYhjDWq6lNfWOdgUfI6FbGSWushGAMg/edit#gid=0",$J$1&"!A4:A26"))),match($J$2,index(importrange("https://docs.google.com/spreadsheets/d/1mAssNMTGXcMcuYhjDWq6lNfWOdgUfI6FbGSWushGAMg/edit#gid=0",$J$1&"!A4:H4"))))

Here is my edit to that formula structure (which should work):

=INDEX(IMPORTRANGE("1mAssNMTGXcMcuYhjDWq6lNfWOdgUfI6FbGSWushGAMg",$J$1&"!A4:H26"),MATCH($A36,IMPORTRANGE("1mAssNMTGXcMcuYhjDWq6lNfWOdgUfI6FbGSWushGAMg",$J$1&"!A4:A26"),0),MATCH($J$2,index(IMPORTRANGE("1mAssNMTGXcMcuYhjDWq6lNfWOdgUfI6FbGSWushGAMg",$J$1&"!A4:H4")),0))

Notice that you only need the spreadsheets ID number for IMPORTRANGE, not the entire URL. This just makes reading such formulas easier.

You also had mismatched sets of parentheses. This was your biggest issue.

And I recommend using the third parameter of MATCH to indicate what kind of match you're looking for. (Here, I assigned 0, which means "exact match only.")

Hopefully, you can use that as a model for editing your other formulas.