Apple storage

So to explain the problem in a nutshell, my iPhone storage is 128gb and system data keeps on taking space, whenever i delete any apps, files or photos even messages from texts i get new space but then it quickly gets taken by system data, what do i do to fix this issue and would i have to do a hard reset of my phone? (It seems from everything i am doing its also been slowing my phone down a lot to the point it is making apps {even settings} crash or inoperable) (I have an iPhone 15 and i am running on iOS 18.5)