Hello

About storage on your device and in iCloud - Apple Support

I'm not sure if you've already checked this and you know for sure that Photos are what's taking up all your space?

How to check the storage on your iPhone, iPad, and iPod touch - Apple Support

So if Photos is the big space killer for you, you can use iCloud Photos to free up space on your device by using the Optimize Storage option..

Set up and use iCloud Photos - Apple Support

Buy more iCloud storage - Apple Support

OR you could just transfer them to a computer and remove them from your phone..

Transfer photos and videos from your iPhone, iPad, or iPod touch - Apple Support

OR yes, you could simply delete them

if you are experiencing an issue that has been seen a lot lately, where 'other' is taking up a bunch of your space.. try updating to the latest iOS 13.6.1

Clear Other storage on your iPhone or iPad - Apple Support

If you need more space for an update - Apple Support