WordPress filter by custom taxonomy and keyword search

I have a script which is not working properly, may I please have a second pair of eyes. I need the script to rememver which category from the select list is seleted when displaying results and I also need the keyword search to work independently or together with the taxonomy select filter.

Please have a look at my script below:

get_header(); ?>

<?php 
/**  **/
$searched = $_GET['searched'];


?>

<div id="main-content" class="main-content">

    <?php
        while ( have_posts() ) : the_post();
            get_template_part( 'content', 'page' );
        endwhile;
    ?>

    <?php
		// If the taxonomy term has previously been selected from the dropdowm menu, grab it
		$term = isset( $_GET[ 'foundry-category' ] ) ? sanitize_text_field( $_GET[ 'foundry-category' ] ) : false;

		// In this section, set selected and taxonomy_query values before creating the taxonomy dropdown & getting WP_Query results
		$selected = '';
		$tax_query = '';
        
		if ( $term ) {

			// Get all posts with the selected taxonomy term
			$term = get_term_by( 'slug', $term, 'foundry-category' );
			if ( ! empty( $term->name ) ) {

				// Set the 'selected' value that we'll use to show which option in the dropdown menu is the currently selected one
				$selected = $term->name;

				// Set the taxonomy to 'tools' and the term to the selected term. We'll use these to filter the posts, below
				$tax_query = array(
					array(
						'taxonomy' => 'foundry-category',
						'terms'    => $term,
					),
				);
			}
		}

        // search arguments 
        if( $searched != '' ) {
            $args['s'] = $searched;
        }

        // pagination 
        $paged = get_query_var( 'paged' ) ? get_query_var( 'paged' ) : 1;

        // loop arguments
        $args = array(
            'post_type' => 'foundries',
            'orderby' => 'title',
            'order'   => 'ASC',
            //'posts_per_page' => -1,
            'posts_per_page' => 20,
            'paged' => $paged,
            's' =>  $keyword,
            'tax_query'      => $tax_query,
        );

        // execute loop
        $loop = new WP_Query( $args ); 
    ?>

    <div id="foundries-list" class="container">

        <div class="foundry-search-filter">
            <div class="block-filter block-category-filter">
                
            </div>

            <div class="block-filter block-search-form">
                <form class="form-search-filter" action="<?php the_permalink(); ?>" method="get">
                    <div class="form-item-wrapper">
                        <?php
                            // Category Filter
                            /*
                            wp_dropdown_categories(
                                array(
                                    'orderby'         => 'NAME',		// Order the items in the dropdown menu by their name
                                    'taxonomy'        => 'foundry-category',		// Only include posts with the taxonomy of 'tools'
                                    'name'            => 'foundry-category',		// This field is needed for submitting the form
                                    'value_field'     => 'slug',		// This field is needed for submitting the form
                                    'show_option_all' => 'All Foundries',	// Text the dropdown will display when none of the options have been selected
                                    'selected'        => $selected,		// Set which option in the dropdown menu is the currently selected one
                            ) );
                            */
                            $terms = get_terms([
                                'taxonomy' => 'foundry-category',
                                'hide_empty' => true,
                            ]);
                        ?>
                        <select name="foundry-category" id="foundry-category" class="postform">
                            <?php foreach($terms as $cat) {
                                echo '<option value="'.$cat->name.'">'.$cat->name . '</option>';
                            }?>
                            <option value="" selected="selected">All Categories</option>
                        </select>
                    </div>
                    <div class="form-item-wrapper">
                        <input type="text" name="searched" id="searched" placeholder="search" value="<?php echo $searched; ?>">
                    </div>
                    <div class="form-item-wrapper">
                        <span class="search-btn dflex-center">
                            <input type="submit" value="Search">
                        </span>
                    </div>
                </form>
            </div>
        </div>

        <?php if( $loop->have_posts() )  : ?>

            <div class="foundries-list-wrraper">

                <?php while ( $loop->have_posts() ) : $loop->the_post(); ?>

                    <h1><?php the_title; ?></h1>


                <?php endwhile; ?>

            </div>

        <?php endif; ?>

    </div>

</div>