HELP!!!! “Other” system storage is HUGE after restoring Iphone

The story started when my Iphone started to feel laggy all the time. Suddenly it restarted by itself and it got stuck in an Apple logo bootloop.

After series of attempt to turn it on by doing hard restart etc, I decided to restore it using Itunes in DFU mode.

After several failures of restoring my iphone (5-7 times) I succeeded to turn my iphone on again.

But I immediately recognized that my Iphone was still laggy even when it was like new and had no data.

After checking the storage of my iphone I saw that the “other” data was HUGE!!! And it kept growing and growing in a short time!!!

Now it takes already 64GB OUT OF 128GB!!!

Please help me