There are three workarounds for the issue.
1.Use the default form in the list.
1.1 When you add the attachment firstly, it will display the URL of the attachment like the picture below. But you cannot click the URL to open the file.
1.2 After that, when you edit the item, you can click the file name and it will open the file in the office application directly.
2. Use InfoPath form.
2.1 You could customize the form in the InfoPath form. Add the rich text box and set the value as the attachment field.
2.2 After that, when you add attachment, it will not display the URL of the attachment in the first time, when you edit the item, it will display the URL of the attachment. If you have multiple attachments, it will display in one line, you should break the line.
2.3 If you want to edit the file, you could click the aa.docx and click “open”. It will open the file in the office application.
3. Use library.
You could consider using library to store and edit the documents.