Filters the Yoast meta title and meta description on the profile page to display the user's display name and biography.

my_pmpro_profile_page_meta.php

<?php
/**
 * Filters the Yoast meta title on the profile page to display the user's display name.
 *
 * @param string title The current page's generated title.
 * @return string The filtered title.
 */
function my_pmpro_profile_page_meta_title( $title ) {
	global $pmpro_pages;

	// Return early if we're not on the profile page.
	if ( empty( $pmpro_pages['profile'] ) || ! is_page( $pmpro_pages['profile'] ) ) {
		return $title;
	}

	// Get the profile user's display name.
	$pu = pmpromd_get_user();
	$display_name = pmpro_member_directory_get_member_display_name( $pu );

	if ( ! empty( $display_name ) ) {
		$title = $display_name;
	}

	return $title;
}
add_filter( 'wpseo_title', 'my_pmpro_profile_page_meta_title' );

/**
 * Filters the Yoast meta description on the profile page to display the user's biography.
 *
 * @param string $description The current page's generated meta description.
 * @return string The filtered meta description.
 */
function my_pmpro_profile_page_meta_description($description) {
    global $pmpro_pages, $current_user;

	// Return early if we're not on the profile page.
	if ( empty( $pmpro_pages['profile'] ) || ! is_page( $pmpro_pages['profile'] ) ) {
		return $description;
	}

	// Get the profile user.
	$pu = pmpromd_get_user();

	// If a bio is set, update the meta description with it
	if ( ! empty( $pu->description ) ) {
		$description = $pu->description;
	}

	return $description;
}
add_filter( 'wpseo_metadesc', 'my_pmpro_profile_page_meta_description' );