now there is an old list page on the mobile side, as shown in the following figure:

there is a child list under it. When the user clicks on the parent list item, the front end will request the backend to return the child list under this category, and then insert the page. In this way, there will be a time interval when the user clicks on the list item to the child list and appears on the page. In addition, in the case of sub-list expansion, sliding the entire list will cause stutter, so I would like to ask the gods what suggestions do you have for the optimization of this list page? Thank you!