Paperless-ngx is great, but it is particularly bad at handling PDF documents. Roughly half my documents just won’t import.
https://github.com/paperless-ngx/paperless-ngx/issues/3933
https://www.reddit.com/r/selfhosted/comments/yfjxww/paperlessngx_not_all_pdf_files_can_be_imported/
There are a number of ways to install nextcloud, and docker is only one of those.
Yes, NC isn’t ideal in many ways, but it shouldn’t be as painful as you’re describing to run it.