Sharepoint files

How to check if files exist in a sharepoint site and download the file based on naming convention?

You have multiple options?

  1. map a network drive and name it as Z and use Z to check and copy
  2. use UNC and directly connect with sharepoint
    e.g. \Servername\sites\folderview\

Do we have any sharepoint activties in ui path to achieve this?

The site which i am working on doesnt provide access to open it in a file explorer

if it’s SP and accessible then surely it can be mapped.
yes, there are activities and you can use it.

Can you pls suggest the activity?

Sorry, I never tried interaction with SP using any activity.
You can search in packages, there are few from Microsoft and authenticated developers which you can use