Mobile app working slow

I have been using Zoho Notebook for over a year. I find this app brilliant in its simplicity and the note cover grid view is its best feature. However, there is one thing that prevents me from using it. The application often takes a few dozen seconds to start up after opening the note. When I finish editing and close it, the notebook view is displayed and no operation can be performed. The problem only disappears after restarting the application. Have you thought about introducing a premium subscription feature? If the application's smoothness does not improve, I will have to move all my notes to Evernote, but I would like to avoid it until they introduce a grid view with note covers, which unfortunately is not expected to happen.