Impossible to do modification when all products are selected ?

Hi, when I select my products (all) to apply a modification like for example : deleting or applying a discount %. I always receive an error message with : “This page has stopped responding. Please refresh and try again”.

I always had this issue, but till now it was okay for me. Now I have 5000 products and it starts to clearly be really nervous to make modification. I tried different browser and computers.
Anyone can help me?

Thank you and best wishes for 2021 !!