This is super simplified, but this is how you would do it:
Do a flow with a trigger based on recurrance, run it every day on a schedule
Create a String variable called "EmailBody"
Create a Variable and use an expression to get todays date
Create a variable and use an expression to get todays date + 30 days
Do a Get Items from your SharePoint list that match the date between today and today + 30 days
Then do a Apply For Each result in SharePoint
Then do an Append to String and add some formatting to the EmailBody. This would build a single list of items that would go into your email.
Then the last step would be to Send an Email and include the EmailBody.
