I changed the following additional configuration and it worked, thanks to @Ken Lee for their helpful comment.

upload_max_filesize = 20G
max_execution_time = 3600
max_input_time = 3600
memory_limit = 4G

Seriously, does StackOverflow have to be so toxic? I asked chatGPT and it helped me only partially, pointing out post_max_size and www-data permissions, some configuration in .htaccess. There was no other resource and the error was vague. Ken's comment solved the problem pretty easily, was it that hard? What benefit have -1 without feedback and pesky comments brought about? I'm a member for 7 years and I have almost 5k points, not a noob who cannot speak English.