Hi,what do you mean by previous page ?
After successful login you can make the Product detail page as default home page / Landing page in role based home page. Or even in default home page selection also,you can map the product details page. By default mendix home page (Home-Web) will be available.
Yes this is possible, in the navigation you will have to call a microflow as a default home page for the user, put some condition in it to redirect the user where you want.
You will have to download the module sign in microflow, to make some action in the microflow called after a login in, in that microflow retrieve the page where your anonymous user was, store that information, and in the microflow of the default home page of the user, you will retrieve that information to redirect correctly the user.
This is the solution that worked for me, but maybe there is other ways to do it.
And of course be carefull with the security.