Using serverside PDF library without composer

Hello all,
thanks again for making codeigniter 4 - it works perfect for me.
I have the following question / problem:
I have a CI4 project with a lot of stuff already inside. Now, I need to add PDF-creation on server side. I previously used a client-side library to generate pdfs in javascript.
In our project, I can not use Composer to install something like TCPDF.
How would I go from here to get a library installed in my existing setting without using composer?

If anyone has an idea or a tutorial I could follow, I would be more then thankful for that.

Thanks a lot in advance and have a nice week!
Paul

Hello,
this page can help you :
https://forum.codeigniter.com/thread-80009.html

Thank you very much! This already fixxed the issue.
Wasn't using the autoloading properly.

Thanks for giving me the hint!