How can i use MY Config File -> K_TCPDF_EXTERNAL_CONFIG not working

[susanne99]

I'm desperate.
I'm using TCPDF 6.7 with Laravel 11.
I want to use my own tcpdf_config.php in my laravel config folder.
Why? because I don't want to rewrite the config in the vendor directory with every tcpdf update.
To do this you have to set the 'K_TCPDF_EXTERNAL_CONFIG' in MY config file to true.
after that, "php:artisan config:cache" throws an error: "'K_TCPDF_EXTERNAL_CONFIG" is already defined.
I've been trying to fix this problem for hours - no chance.
So the question: How can I use my own "tcpdf_config.php"???