How do I prevent my employer from accessing PCs at my home?

For an indeterminate amount of time, I will have a work laptop, which I can bring home. My boss told me that she wants me to leave it on, so my employer’s IT can push out updates to the work laptop, etc. I understand what my employer wants. But I am not comfortable with the idea of exposing all my personal computers at home, to my employer. That isn’t their business, either.

So, first question is, does having my work laptop turned on and connected to my home Wi-Fi enough for my employer to push updates to it? Networking is not in my wheelhouse, so I don’t know if that’s possible or not. I would think that I would have to connect to my employer’s domain for them to push updates to the laptop 24/7. Am I correct or can just having it powered up and connected to my home Wi-Fi enough for them to push updates to the laptop? And if the answer to that question is Yes, then can they look at any of my home machines?

If the answer to my last question is yes, then I have an option of creating a guest network on my router. Would that be sufficient so I could put the work laptop on the guest network and leave the laptop powered up 24/7, and will that prevent them from accessing all the other machines at home?

BTW, I did research this question but the answers I found weren’t satisfactory to me.