AFAIK it's not possible to select an item without a user action. There is a way around that I use sometimes, you would need a helper object with an association to items in your list. So when you 'select' a list item, the association between helper entity and the list entity is set. You can use dynamic classes to highlight the 'selected' list item in a specific way so that it looks selected.
You can use logic in a microflow to set the association before opening the page.
anyone can help?