The main thing is how focused it is on handling pdf. It does not rely on a specific file format like reMarkable for annotations, that need then to be exported to a flattened pdf file. The annotations are native, thus editable, cross-platform (highlights can be extracted in Zotero for instance, and Zotero's full pdf collection can be synced with the tablet), etc, it is much cleaner for bibliographic work. The A4 model is also a plus for many people. Then, every other distracting feature are basically stripped out (lacking crop margins though), and you get these light and specialized tablets. My only wish for these devices would be some repairability (replaceable battery) and open software (or at least a better Linux support).

Thank you for your suggestion and the link. The first setting is indeed set to false, but changing the second from true to false does not solve this issue. To be more precise, when Librewolf is not running, clicking a link actually opens it to the foreground. However, when it is already open, it does not come in the foreground.

I cannot help for the first problem, I do not have it. For the second, I have experienced similar issues and moved to the "Dark Background and Light Text" extension, which works better in my case.