Hi Girish,
I tried the above and I received the following error message when I tried to save the binding ref to the attachment field:

I tried the below combinations as a fix but with no success: $.simple_submission.Attachments, /Attachments, $.Attachments
Please DM me with some time slots when you would be available.
Many thanks for looking into this.
In preparation for our call, I'm listing some errors that I can see in the logs:
- *ERROR* [...] POST /content/forms/af/.../guideContainer.af.submit.jsp HTTP/1.1] com.adobe.aemds.guide.servlet.GuideSubmitServlet Could not complete Submit Action due to java.lang.NoClassDefFoundError: Could not initialize class org.apache.commons.beanutils.BeanMap
org.apache.sling.api.scripting.ScriptEvaluationException: java.lang.NoClassDefFoundError: Could not initialize class org.apache.commons.beanutils.BeanMap
at org.apache.sling.scripting.jsp.jasper.servlet.JspServletWrapper.wrapException(JspServletWrapper.java:607) [org.apache.sling.scripting.jsp:2.6.3.T20240918101441-6fe463b]- Caused by: javax.servlet.ServletException: java.lang.NoClassDefFoundError: Could not initialize class org.apache.commons.beanutils.BeanMap
at org.apache.sling.scripting.jsp.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:902) - Caused by: java.lang.ExceptionInInitializerError: Exception java.lang.NoClassDefFoundError: org/apache/commons/collections/Transformer [in thread "... POST /content/forms/af/.../guideContainer.af.submit.jsp HTTP/1.1"]
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
errors when selecting a custom XDP template for DoR
- *ERROR* [...] POST /libs/fd/fm/content/basemanage.json HTTP/1.1] com.adobe.aem.formsndocuments.service.impl.DoRTemplateServiceImpl Error in getting LMT
com.adobe.aemforms.fm.exception.FormsMgrException: com.adobe.aemforms.fm.exception.FormsMgrException: com.adobe.aemforms.fm.exception.FormsMgrException: Invalid XFA Adaptive Form at path:/content/forms/af/.../myform. xdpRef property was not found.
at com.adobe.aem.formsndocuments.service.impl.FormsRelationServiceImpl.getRelatedChildAssets(FormsRelationServiceImpl.java:151) - Caused by: com.adobe.aemforms.fm.exception.FormsMgrException: com.adobe.aemforms.fm.exception.FormsMgrException: Invalid XFA Adaptive Form at path:/content/forms/af/.../myform. xdpRef property was not found.
at com.adobe.aem.formsndocuments.service.impl.FormsRelationServiceImpl.getRelatedChildFMAssets(FormsRelationServiceImpl.java:218) - Caused by: com.adobe.aemforms.fm.exception.FormsMgrException: Invalid XFA Adaptive Form at path:/content/forms/af/.../myform. xdpRef property was not found.
at com.adobe.aem.formsndocuments.util.FMUtils.getDORRefPath(FMUtils.java:588)
Guessing they are coming from this config:

Thank you!
Confirmed with engineering, this use case is not supported.
As of now only attachments can be saved in share point list.
please log a feature request to get this capability in the product .