A way to enable users to delete

Is there a way to do that users can delete their own posts and chat messages? Instead of that the admin of the app have to do all the work?

you have to do some work right here
1st you need to add Row ID for the items table
2nd add email column in the items table and in glide in the add form you must add a text entry and set the data to the email column and the default value is user email and hide the text entry if you want
3rd in the item details enable edit form and set the condition to user email is item email

If you are talking about the native “Chat” and the native “Comments” then we don’t have a way to enable users to delete them.

To enable that functionality, you have to build your own public/private chat and/or comments functionality, but that will consume a lot of rows.