Remove huperlink from Blog single post H1 titles

But you like to remove only the link option on single post not on the archive post list?

You can see here that i inserted a ternery operator on setting the link in the avia_default_title_filter function on helper-post-format.php
this code here is different to the standard code:

$output .= is_singular() ? $current_post['title'] : "<a href='".get_permalink()."' rel='bookmark' title='". __('Permanent Link:','avia_framework')." ".$current_post['title']."'>".$current_post['title'];
$output .= "<span class='post-format-icon minor-meta'></span>";
$output .= is_singular() ? '' : '</a>';

so put this to your child-theme functions.php:

function avia_default_title_filter($current_post){
	if(!empty($current_post['title']))
	{
		$default_heading = is_singular() ? 'h1' : 'h2';
		$args = array(
					'heading'		=> $default_heading,
					'extra_class'	=> ''
				);
	
		$args = apply_filters( 'avf_customize_heading_settings', $args, 'avia_default_title_filter', array( $current_post ) );
		
		$heading = ! empty( $args['heading'] ) ? $args['heading'] : $default_heading;
		$css = ! empty( $args['extra_class'] ) ? $args['extra_class'] : '';

		$output  = "";
		//$output .= "<{$heading} class='post-title entry-title ". avia_offset_class('meta', false). "'>";
		$output .= "<{$heading} class='post-title entry-title {$css}' ".avia_markup_helper(array('context' => 'entry_title','echo'=>false)).">";
		$output .= is_singular() ? $current_post['title'] : "<a href='".get_permalink()."' rel='bookmark' title='". __('Permanent Link:','avia_framework')." ".$current_post['title']."'>".$current_post['title'];
		$output .= "<span class='post-format-icon minor-meta'></span>";
		$output .= is_singular() ? '' : '</a>';
		$output .= "</{$heading}>";
		$current_post['title'] = $output;
	}
	return $current_post;
}

and by the way you can change here the tag of the heading on archives and single post on this line above:
$default_heading = is_singular() ? 'h1' : 'h2';
this is ternery operator again – if you have a single post it is h1 – else h2

Maybe this should be the standard on helper-post-format.php – because it does not make sense to link to the post itself