I have:
A main custom post type – ‘Cards’ – each post showing its ACF repeater custom field – ‘operations’ – with the following sub-fields: ‘add/remove’, ‘amount, ‘value’, ‘date’.

Let’s say the fully operational website will have 500 Cards posts, with about 50/100 operation rows each.

What would be the less stressing solution, to keep querys and Database load reasonable?

• Keeping my first choice and use custom fields with ACF repeater, inside the Cards posts.
• Creating a dedicated custom post type ‘operations’, one new post for every single repeated row, and query all the related ‘operations’ post from within the ‘Card’ post they belong to.

Card post & operation as ACF repeater fields:

    Card[post]
            operation [custom fields]
            operation [custom fields]
            operation [custom fields]
    ...
    Card
    Card

Card post & Operation as post:

    Card[post]
            {wp_query all the related operation[post], return operation[post] fields}
    ...
    Card
    Card

    Operation[post]
            [custom fields]
            [custom fields]
            [custom fields]
    ...
    Operation
    Operation

Any suggestion will be most appreciated.