I have been using Lightroom for some time now I recently lost my iPhone and failed to restore backup on my new phone because of smaller memory but now I have new phone with bigger memory and I restored Lightroom but all my pictures gone after signing in please how do I get all my photos back
Are you able to restore the backup of your original phone #1 (that has all your Lightroom photos)? It sounds like this is not what you are restoring to your newest phone?
Is the issue that you only have a backup of your 2nd phone (which did not have all your Lightroom photos), and this is what you are applying to your newest phone? If so, do you possibly still have a backup of your original device above?
The free version of Lightroom keeps photos only on the device. Lightroom does not sync to cloud storage unless you subscribe.
The only thing that could help here is if you had backup of your previous device from when the free Lightroom had all the photos -- only with this could you restore a backup with all the photos onto your device.