Content files in nodes do not associate

Background:

We admin a site for medicine students in Gothenburg. Our users submit study content, self-constructed mockup exam questions, old exams, course summaries etc., to share and partake with each other on the site. The site is driven by donations. Kandidaterna.se has existed for about 15 years and is intergral to the study experience for future physicians.

None of the admins, me included, have any experience in Drupal - only Wordpress - but inherited the project that has about 1200 active users each year in rotation. It's an honor to give back to the community. While normally it's a manageable bit of work to maintain, now we have run into a critical error to the system.

Main issue:

Since cirka 2022-10-31 our new content nodes do not associate the uploaded files. The Add content seems to create nodes like normal, the update process completes, but the files are not displayed in the resulting node. Old nodes sitll display their associated files.

Please see images below (Imgur link for all images):

Working as intended, almost: File, .pdf for example, is associated. No user pictures are ever displaye,d and we can't figure out hwo to fix it since it's most likely associated with the private nature of the libraries, but it's a tertiary issue.

Not working: Content still created, but the file is omitted. Example is perchance poor, but the other descriptive fields do work as intended.

Steps taken and plan:

• I have tried googling the issue to no avail.
• I have taken full backups of the database and files.
• I have found by FTP that the files do get uploaded with the rest of the files to the private library, but are not associated. See photo below.



• My next step, if this was a Wordpress installation, would be to update the core Drupal. However, our version 8.9.8 seems a bit tricky to update, and manual checks return error messages. See below:
  
  

There is a heavy pressure from our peers to fix this issue, but I am in the middle of a dissertation, and my fellow admins know even less about Drupal or for that part web/design/database work than I do, and thus I try to extend a hand here on the forums.

What would you suggest that I do? Given that most of you are confirmed users with good history behind you, I would be inclined to share access to the site if you need more data to solve the issue. I am at this point grateful for any lead I can get, and thank you for reading to the end if you've done so!