I want to check a IF formula by using the IFS function

I have the following IF function, which tells us the source of some data in Excel.

=IF(D168=T168, " ", IF(AND(S168=0, R168<>0), "Invalid number", IF(AND(R168=0, Q168<>0),"Invalid Text", IF(AND(D168=0, T168<>0), "Source X", IF(AND(T168<>0, T168<>F168, OR (T168=G168, T168=O168, T168=P168)), "Source Y", " ")))))

Now I want to check that this formula is pulling the right source with an IFS function. I have tried IFS(D168=T168, " ", S168=0 R168<>0, "Invalid Number") but this formula returns an error.

I want to basically translate the IF formula above into an IFS formula.