Thank you @OliverRodrigues for your response.
I have implemented the similar kind of solution but using Power Automate Flow and SharePoint.
1. Created a custom entity - let's say Data Import
2. Enabled SharePoint integration on that entity.
3. Expose the Data Import entity on portal.
3. From portal, user can create a new Data Import entity record and upload excel sheet via SharePoint document area
4. I have built a Power Automate flow to process the document from the document location and upload/import into Dataverse table.
Hope this will help for everyone!