Wrong pagination size after filtering category product collection with custom condition

I am trying to filter the category products collection on the basis of custom product attribute, i used many ways to override the collection but every method is filtering the records per page rather than getting all the matched product before paginating.

We are overriding this file: MagentoCatalogBlockProductListProduct.php
Method we are overriding: _getProductCollection()

This is the code reference:

public function _getProductCollection()
    {
        if ($this->_productCollection === null) {
            $this->_productCollection = $this->initializeProductCollection();
        }

        $jayParsedAry = [
            [
                  "attribute" => "custom_attribute", 
                  [
                     [
                        "eq" => "", 
                        [
                           "null" => true 
                        ] 
                     ] 
                  ] 
               ], 
            [
                              "attribute" => "custom_attribute", 
                              "finset" => "1111" 
                           ], 
            [
                                 "attribute" => "custom_attribute", 
                                 "finset" => "1112" 
                              ] 
        ]; 
        $this->_productCollection->addAttributeToSelect('*')->addAttributeToFilter($jayParsedAry);
        return $this->_productCollection;
    }

There are total 19 filtered records, but showing 109. On the first page, there are only 6 records showing, instead of 12 per page. Please suggest a proper way to implement filters.