Crashing Apps on Iphone 7

Hi,

All apps keep crashing on my Iphone7, especially apps like Instagram, Wechat and Shopee Malaysia keep jumping out back to the home screen all of a sudden.

When I am typing, it becomes laggy as well, the whole experience is just not smooth at all.

I wonder is there anything I can do to help with this issue... I have rebooted my iPhone back to the factory setting and it is still the same... Please help...

Appreciate your reply and thank you in advance.

Kind regards,

Chloe.