Since 2007, iPhones never had the microSD slot so buying larger storage for future proofing is what you should have done... Also, apps of today are already hundreds of megabytes without user data so just using the app for several hours already adds several megabytes to the used storage...
I have started from scratch with my iPhone 13 Pro 512GB running iOS 17.7 and browsing Facebook since yesterday, which is 341.7MB app size, accumulated 590.6MB of documents and data storage... This is just the second day since performing Erase All Content and Settings yesterday...