PHP functions to retrieve an SVG file and load it inline. Also supports adding new attributes to the SVG that aren't already there.

get-svg.php

<?php
function get_html_attributes(array $atts) {
  return array_reduce($atts, function($carry, $name) use($atts) {
    $value = $atts[$name];
    return "$carry $name=\"$value\"";
  });
}

function get_svg( string $name, array $atts = [] ) : string {
  $file = get_template_directory() . "/dist/images/$name.svg";

  // Bail if the file can't be found
  if( ! file_exists( $file ) ) {
    return '';
  }

  $svg  = file_get_contents( $file );

  // Bail here if file_get_contents fails
  if( $svg === false ) {
    return '';
  }

  $new_atts = get_html_attributes( $atts );

  return preg_replace( '/<svg/', "<svg $new_atts", $svg );
}