I rebooted my phone and downloaded it again and it seems that it is running normal now. My internal storage was almost full when I downloaded it maybe it affected the app(I am not sure). Anyway, thanks for the inputs.
It sometimes happens to me with my Samsung phone even on other apps it's slow down when the memory is full I think that is why it's running normally now it's because restarting the phone will help to clear up all running apps in the background.
I think new phones have a built-in tool that can clean up memory like mine I can go to device care and click memory then tap the clean button to clean up all running apps on the background. So it doesn't need to reboot the phone. You can try that on your Poco phone.
I search a bit on youtube it seems you can find that tool under settings>about to clear up some space and memory.
Here's the youtube video https://www.youtube.com/watch?v=UErSTNhFyiE