Hi, Please correct me if misunderstand. You want to build solution SharePoint site with Out of Box features. This could be a independent portal also.
There is two approach 1st is easy solution.
Create Team site, Modify Pages, List as per requirement using SP Designer, So its easy development and fast also. So basically we are creating Production ready copy. For any future update or maintains, is catch its bit painful but can be achieve with certain rule and regulation. So build UI without any hard code URLs so it will work if you move / Migrate this site any other site Collection, So try to minimize the post migration fixes. I followed this approach some of SP2010 to SPO migration and it works with little pain when you migrate / Move to new environment.
Another approach is more like techy or Visual Studio friendly solution where everything is in source code(TFS). So its SharePoint App developed using Visual Studio built all forms and list and any Out of Box feature. Also you can add basic data as part of solution. But can't add any big list data. So post production each deployment migration is also important factor. Otherwise, You will end up modifying current production instance only. This approach will take more development effort. Also You will be using costly SharePoint developer for longer time. Also each deployment data migration is also critical factor.
There is two approach 1st is easy solution.
Create Team site, Modify Pages, List as per requirement using SP Designer, So its easy development and fast also. So basically we are creating Production ready copy. For any future update or maintains, is catch its bit painful but can be achieve with certain rule and regulation. So build UI without any hard code URLs so it will work if you move / Migrate this site any other site Collection, So try to minimize the post migration fixes. I followed this approach some of SP2010 to SPO migration and it works with little pain when you migrate / Move to new environment.
Another approach is more like techy or Visual Studio friendly solution where everything is in source code(TFS). So its SharePoint App developed using Visual Studio built all forms and list and any Out of Box feature. Also you can add basic data as part of solution. But can't add any big list data. So post production each deployment migration is also important factor. Otherwise, You will end up modifying current production instance only. This approach will take more development effort. Also You will be using costly SharePoint developer for longer time. Also each deployment data migration is also critical factor.