Will all my photos that I backed up be available if i sign in my icloud on a laptop ? I want to start fresh on my device but I still want access to everything after

You cannot access iCloud Backup data at iCloud.com. You can only use a backup to restore a device or set up a new device. See: Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

You can view synced data at iCloud.com and it will automatically sync with your iPhone after you erase it using instructions in Erase iPhone - Apple Support if you turn the sync options on again.

To sync photos, see Set up and use iCloud Photos - Apple Support

For contacts, see: Set up iCloud for Contacts on all your devices - Apple Support

To sync other data from an iPhone, go to Settings > [username] > iCloud.

Data that is synced with iCloud will not also be included in an iCloud Backup -- the data is only stored once in iCloud. Syncing has the advantage that it happens dynamically when data changes while Backup only happens periodically. Synced data also has the advantage of being accessible at iCloud.com.