PHP: fopen … permission denied … unable to find a solution [closed]

i have read a lot about the fopen permission denied error. But i am not able to find a solution. I am aware that this is a permission problem. Please have a look at my settings and what i have done so far to solve the problem:

Almalinux 9
/var/www/html

in /var/www/html i have script called testing.php and in the subdirectory /var/www/html/upload/tmp/ there exists a file called readtest.csv

This is the code:

    <php>
    $filename = "/var/www/html/upload/tmp/readtest.csv";
    $handle = fopen($filename,"r");
    
    $filename = "/var/www/html/upload/tmp/writetest.csv";
    $handle = fopen($filename,"w");

    echo exec("whoami");
    </php>

If i run the script it can read the readtest.csv file without any errors. But if i try to write the file writetest.csv it show “permission denied”.

The result of whoami is “apache”

I open a shell logged in as root and run:

sudo chown -R apache /var/www/html

The owner of the folder and the owner of the file is “apache”
I checkd running
ls -la in /var/www/html/upload/tmp/

drwxr-xr-x. 3 apache apache 43 10. Jan 10:42 tmp

But i am unable to write from the php script to this directory. But i am the owner! I dont know where to look next to solve the problem?

Why apache can not write to its own directory?