Managed to find the problem. In htaccess the following piece of code causes the error
<FilesMatch “.(php4|php5|php3|php2|php|phtml)$”>
SetHandler application/x-lsphp74
</FilesMatch>
After deleting it, i have no problem with the local page. Don’t know if the problem is with php 7.4 itself or what is specifically causing the problem, but i can finally work locally, so I’m happy for now.
I don’t understand why this is only happening with newer backups. Does anybody know where the problem could be?