Capabilities of Wordpress & wp_postmeta

I would like advice on the capabilities of Wordpress.
I would like to migrate my current web to Wordpress.
In the current web I have fields that do not exist in WP, it's no problem :wink:. I created with Avanced Custom Fields plugin.

ACF (Avanced Custom Fields pluing) creates fields in the wp_postmeta table. If I import all fields there, the table can have more than 2,000,000 rows.

I imagine this is a problem for WP, or not?

Is there some other method?
The current web works with 11 related tables. Import all data into to two tables (wp_postmeta and wp_post) It's may very 'animal', not? :slight_frown:

Thanks for your time, and I feel my bad English.