login,roles(admin,client),subscriptions

i need a lot of features, with database.

A login, a custom checkout, Roles(client and partner) , subscription etc.

What do u suggest is the best way to go?

I see that is not enough what i have done in website?

Are these possible to do?

SS DOES NOT support the following.

A built-in database. Not one that you can define your own tables and fields in anyway. You can of course use services like Google Sheets and others to potentially add a database to your site. But you'd need to research what can be done in that area.

Modification of the checkout page. It is an SS security feature.

SS does have the following.

Member areas and subscriptions but you'd need to read the documentation to see if they would meet your needs.