Characterization Occurs When Loading CSV Files

I'm a beginner in PHP.

I am currently preparing a questionnaire form.

アンケート Fill in the questionnaire
②Input Confirmation Form
③Answer completion page (at this point the questionnaire will be printed in a CSV file)
④Read and view CSV files here page for answers

This is the configuration.

As of 3

// Preparing to write an array to a csv file 
$title=['Name', 'Attendance Number', 'Email Address', 'Gender', 'Hobby', 'Last Year's Best Memories', 'Resolution of the Year']; 
$vararray = [$myid, $number, $mail, $gender, $hobby, $lastyear, $thisyear]; 
// Convert string from UTF-8 
mb_convert_variables('SJIS-win', 'UTF-8', $title); 
mb_convert_variables('SJIS-win', 'UTF-8', $vararray); 
// Write to file 
$handle=fopen('data/data.csv', 'a'); 
block($handle,LOCK_EX); 
fputcsv($handle,$title); 
fputcsv($handle,$vararray); 
block($handle,LOCK_UN); 
fclose($handle);

The code has been written to the csv file successfully.

At this time, I changed the encoding from UTF-8 to Shift_JIS, so when I read in で, the characters get garbled.
When I changed the encoding to Shift_JIS in my browser, the garbled characters disappeared, so when I read it, I understood that it was encoded as Shift_JIS, but I don't know how to return it to UTF-8.
First mb_convert_variables ('SJIS-win', 'UTF-8', $ variable);
I thought I should change it in
but the situation hasn't changed. setlocale(LC_ALL,'ja_JP.UTF-8'); also tried, but it didn't work here

Currently, the code below is not working.

<?php

setlocale(LC_ALL, 'ja_JP.UTF-8'); 
$fp = fopen("data/data.csv", "r"); // Open File 
US>block($fp,LOCK_SH);// File Lock 
while($array=fgetcsv($fp)){// Load file 
    $num = count($array); // line count 
    for($i=0;$i<$num;$i++){ 
        echo'<p style="font-size:12px;">'.$array[$i].'</p>';// Output for now 
    } 
} 
block($fp,LOCK_UN);// Unlock 
fclose($fp);// Close file 
?>

If you know anything about it, please let me know.

Thank you for your cooperation.