@rmcf

Have the same problem on Drupal 10.1.6 at the shared web-hosting with Apache 2.4.58 and PHP 8.1.25. To make custom images styles working and thumbnails visible I have commented option “-ExecCGI” in the file

/public_html/sites/default/files/.htaccess 

and now it looks like this:

# Turn off all options we don't need.
Options -Indexes -Includes -MultiViews
# -ExecCGI

I am not sure is that the safest solution but it works for me

Have the same problem on Drupal 10.1.6 at the shared web-hosting with Apache 2.4.58 and PHP 8.1.25. To make custom images styles working and thumbnails visible I have commented option “-ExecCGI” in /public_html/sites/default/files/.htaccess and now it looks like this:

# Turn off all options we don't need.
Options -Indexes -Includes -MultiViews
# -ExecCGI

I am not sure is that the safest solution but it works for me.