advanced search using min and max area

hello,

i added two fields inside the advanced search form:
– m2 min
– m2 max

to let users to make a search based on a minimum or/and maximum surface area.
to do this i cloned the min / max price fields:

‘mq_min’ => array(
‘label’ => ‘m² (min)’,
‘key’ => ‘_details_2’,
‘type’ => ‘text’,
‘data_compare’ => ‘>=’,
‘data_type’ => ‘numeric’,
‘advanced’ => true,
‘class’ => ‘col-md-3 col-sm-6’,
‘priority’ => 110
),

‘mq_max’ => array(
‘label’ => ‘m² (max)’,
‘key’ => ‘_details_2’,
‘type’ => ‘text’,
‘data_compare’ => ‘=<‘,
‘data_type’ => ‘numeric’,
‘advanced’ => true,
‘class’ => ‘col-md-3 col-sm-6’,
‘priority’ => 110
),

making a research the search url it seems to be correct – https://www.betulleimmobiliare.com/elenco-immobili/?keyword=&offer=rent&location=&listing-type=&min=&max=&mq_min=80&mq_max=90 – but the area fields are ignored in the search results.
what must i do to make the research to work fine?

i also tryed to use this snippet – https://docs.wpcasa.com/article/snippet-custom-advanced-search-fields/?wpkb-rated=1 – to add my new fields but without success, so i have modified the wpcasa advanced search plugin.

hoping for your help i salute you.