MacBook Pro won't sleep with external monitor, keyboard and mouse

I know this question pops up regularly but I haven't been able get a clear answer as it often gets confused with the opposite question, pulling cables, using it in clamshell mode etc.

So I have a M3 MacBook Pro with the Pro chip. I have it connected to a CalDigit TS4 dock with a monitor connected to that. I also have the Apple Touch Id bluetooth keyboard and a Logitech MX Master mouse. Everything works fine but I'm confused about getting the MacBook to sleep at night.

I manually select the Sleep option from the Apple menu and the laptop display goes off as does the external monitor. I'm assuming it is now asleep. I close the lid and the external monitor wakes up and all apps and desktop icons shift over to it. Eventually this display will go off based on the System Settings value for turning displays off.

I'm guessing that what is happening is that by closing the lid on the sleeping MacBook it wakes up into clamshell mode. I don't want it to do this as I don't use it in clamshell mode: I use both the screens during the day. None of the battery/lock screen options seem to help here.

What I actually want to do is put the MacBook to sleep at night and wake it up in the morning. I also want to close the lid to help keep dust off it and the keyboard. I suppose if push comes to shove, I don't mind that too much as it obviously didn't bother me when I had an iMac with external monitor attached!

Edit: the other thing I was trying to find out is the difference in power consumption of the MacBook when sleeping vs display off. And thinking about that it may all be immaterial as the dock stays powered and I pull the MacBook power from there. I'd still like to close the lid without waking up the external monitor though.