Can I setup my new iMac without having access to my laptop?

You don't need your laptop. The iMac will set itself up. Just follow/respond to the prompts when you first turn it on and you're all set.

If you're referring to transferring your files from your laptop to your new iMac, then that depends. If your files are on the cloud, then install/configure the same on your new iMac.

If the files are stored locally on your laptop, then you'll have to set up file sharing on your Mac (or Laptop) and then just transfer whatever files you want.

If it's a MacBook, you can use Migration assistant as well to transfer everything to your new Mac.

By "laptop" I am going to assume you are referring to an Apple MacBook Air, MacBook or Macbook Air. If it is please carefully follow the steps in Setup Assistant and Migration Assistant and your migration will be smooth, quick and dead reliable.

I have no idea what your laptop has to do with this, but if you don't need to transfer old files, you can just skip that step and go.

All Macs can be setup by themselves. No laptop is needed. For two factor verification you will need a second device of some kind but pure setup is automatous.