What's the best way to work with user defined tables / fields. Form or Sheet?

I am developing an app builder and need a way to build custom tables (user can create tables and custom fields with relations)

There are two common approaches for the UX in designing the table and later working with data, but I am not sure which one has more UX advantages for modern SaaS services.

1. Forms

App designer will design the form using a Form and then the custom app user will enter data through the form as well. When data is saved it can be shown in a Grid.

Pros:

1. More controllable (friendly validation especially required)
2. Can add a lot of fields without worrying about the page size,
3. More mobile friendly
4. Better able to add business rules and complex validation.

Cons:

1. Slower to design a new form
2. Slower data entry. No bulk action

2. Sheets
Similar to Excel, app designer can add fields on the sheet directly and app user can enter, edit, delete data on inline cells.

Pros:

1. User is already familiar with Excel
2. Faster design and data entry

Cons:

1. Horizontal scroll
2. Not mobile friendly
3. User can add rows and change cells by mistake

My question is how to make such a decision?