Looping over wordpress meta to create “ ‘s?

Does select("core/editor").getEditedPostAttribute("meta") get the
whole post meta?

Only the meta registered using register_post_meta() or register_meta() with the show_in_rest argument set to true. So for example, the meta can be registered like so:

register_post_meta( 'post', '_postcode_pricing_postal_town', array(
    'show_in_rest'  => true,
    'single'        => true,
    'type'          => 'string',
    // I set this because the meta is *protected*, i.e. the key starts with a _
    // (i.e. an underscore), and when the meta is protected, by default it will
    // not be editable via the REST API (even if the request was authenticated).
    'auth_callback' => function () {
        return current_user_can( 'edit_posts' );
    },
) );

How would one iterate over the resulting post meta (if it gets it all)
getting each, _postcode_pricing_ option, and creating a
<TextControl> for each?

First off, I would suggest you to use useEntityProp to retrieve and update the post meta — see here for more details.

Now here’s an example of how can you correctly fill the panelInputs array with one or more <TextControl> depending on your post meta:

const postType = useSelect(
    ( select ) => select( 'core/editor' ).getCurrentPostType(),
    []
);

const [ meta, setMeta ] = useEntityProp( 'postType', postType, 'meta' );

const updateMetaValue = ( key, value ) => {
    // Clone the existing meta object.
    const newMeta = { ...meta };

    // Update the specific meta only.
    newMeta[ key ] = value;

    // Then set the updated meta.
    setMeta( newMeta );
};

let panelInputs = [];
for ( let key in meta ) {
    if ( /^_postcode_pricing_/.test( key ) ) {
        panelInputs.push(
            <TextControl
                label={ key }
                value={ meta[ key ] }
                onChange={ ( value ) => updateMetaValue( key, value ) }
            />
        );
    }
}

Don’t forget to load the useEntityProp, e.g. import { useEntityProp } from '@wordpress/core-data';.

And in the above example, the <input>‘s label is the meta key.. but I think you’re able of changing that on your own?