How do i delete photos on one device but make sure they are not deleted on other devices?

Ok, so I am not sure if I agree with Sahil, if you sync image files from your iPhone to your storage in your Creative cloud storage original file will be uploaded to your Cloud storage. If you have Lightroom Classic on your laptop a copy of the original will be synced to your laptop. Any changes made on either device will be synced with all devices signed in to your account.

I have mentioned your account since your license is a single user license.

If you do not wish original images on your laptop you can use the Lightroom (cloud-based) app on your laptop then all originals can reside in cloud storage.

https://www.lightroomqueen.com/lightroom-cc-vs-classic-features/

Have a look at the link above.

Hi there,

That images that are synced from Lightroom mobile to Lightroom Classic are previews of original images, and you can remove them by right-clicking on the collection and choosing delete as shown below:

Make sure to check uncheck the option to leave images in Lightroom Classic as shown in the image below:

Also, please make sure that you have all your images locally saved on your phone or on a hard-drive just incase.

Let us know how it goes.
Regards,
Sahil