What has everybody's experience been?
This will be true of all systems. Devs hate adding comments, writing documentation, maintaining tasks/wikis/etc., and everything else that we need them to do. Some people try to make them track their time, which I think is both pointless and unlikely to happen.
The only solution to this is to move it out of the "discipline" column and into the "process" column. For example, I set up git hooks so that a commit will be rejected unless it's tagged with an issue number. And then I have another rule that says that issues aren't accepted unless they have the important fields filled out ("steps to reproduce" for a bug, "user story" for a feature).
It's not perfect, but it definitely creates better habits overall.
This will sometimes make it harder for developers to start working with OpenProject since for many topics, you will need both (e.g., API changes and frontend work). Especially so since the application has evolved for more than 10 years.
We recently did work on a "big picture" documentation for new developers to understand some of the concepts at play: https://docs.openproject.org/development/concepts/
Our developers like tools that support their processes. They just want something that works, and is under active development.
This is something where we know it's painfully missing and is being planned and actively worked on.