Is it possible to connect a NOT gate (74hc04) to connect two separate circuits in parallel?
The X, Y, and Z lines all seem to be connected to multiple NOT gates.  Instead, you only really need three NOT gates, and derive three lines \$\small \overline{\text{X}}\$, \$\small \overline{\text{Y}}\$, and \$\small \overline{\text{Z}}\$ and route those as necessary to the inputs of the next level.