Ask HN: What is good circuit designer and emulator for me?

Hi, I&#x27;m planning to build a 8 bit CPU using TTL logic gates. I&#x27;m having difficulty finding a circuit designer and emulator. Emulation is critical for me since I need to debug before implementing the circuit to lower the costs because logic gates are really expensive in my accessible markets.<p>Logisim was promising before but I had hard time using it.<p>Are there any good circuit emulators for my use case? Thanks.