Storage issue after updating to ios 15

Hi, i updated my phone to new IOS software and then 15.1. After few days of whatsapp my apps started crashing as it showed low storage. Before the update i had enough storage. Now, i freed upto 5 GB space, but the system data is eating all the space. I deleted many apps, files, videos and data from my whatsapp but of no use. After all the clean up i am left with 350 mbs. My phone was stuck for so many times for the first time. My apps keep crashing. Kindly tell me if there is another update to fix the issue or is there any other way to fix the problem? For the reference i am attaching screenshots please have a look on system data.