Why won't mouse click wake-up my iMac?

Thanks, I knew there was a preference somewhere that addressed this, and curious it had been deselected, although I've recently updated to Catalina, so it maybe it reset itself. However, will this also mean that using any other devices, like headphones, phone, speaker, etc. will wake it up as well?

Hey Jake, I think you misunderstood my intent. I don't want any of those other devices waking up my iMac... I've had some bluetooth ear buds, even when back in their case, stay connected, or re-connect, hijacking my sound output, which as you can imagine, is pretty frustrating! Sometimes I feel like throwing all my devices out the window... but then again, there's so much that they do which is great, so I don't... Although, if we could only save the internet, and maybe cell phones with basic functions (call, text, GPS), I could live quite happily ever after. I have an overflowing folder with only manuals & user guides, with more added all the time, and that's the part I hate, the constant re-learning how to do things we've been doing just fine, for even decades, every time we get a new phone, computer, OS, etc, etc... So, no, I don't want anything else waking up my Mac, it does it on its own way too often as it is. ;-)