Help needed with Indirect() and code to reference another worksheet

[MyNameIsNovice]

I believe I am having difficulty with the Indirect() function and getting Excel to return what I wish. The idea is to be checking to see if all pieces of data for each client has come in for the month. If there is at least one piece that hasn't come in I want to know it, if all have come in I want to know that. Countblank will accommodate this. The formatting of this needs to remain basically the same, meaning the lookup table, the worksheet names, the vlookups to return row positions. What certainly can change is the code I am using via Indirect() if there is a better method.

I am attempting to replicate the following which I know works correctly

IF(COUNTBLANK('Data Loads'!G3:'Data Loads'!G4)>0, "blanks","non blanks")

This code is going to be on the worksheet many times, referencing many different columns and rows so I am trying to use a combination of INDIRECT and some Vlookups to return the correct information. I can write most of it via Indirect correctly, at least I think so.

=IF(COUNTBLANK(INDIRECT(("'"&C3&"'!"&B3&VLOOKUP(A3,Clients_Table,3,FALSE))&":"&INDIRECT(("'"&C3&"'!"&B3&(VLOOKUP(A3,Clients_Table,3,FALSE)+1)))))>0,"blanks","non blanks")

However this currently returns #REF. I think that my issue is with the

&":"&

part of the code, and for the life of me I can't figure out how to get that to work. I could also be using incorrect parenthesis. The formula correctly looks like this if I F9 pieces of it:

=IF(COUNTBLANK(INDIRECT("'Data Loads'!G3"&":"&INDIRECT"'Data Loads'!G4"))>0,"blanks","non blanks")

It looks like it is correctly evaluating the two snippets. Any ideas how I can get this to return the correct code referenced above.

Thanks so much!