For people having trouble staying under the 10k characters limit, here is a little tip that could help you if you are willing to adapt your writing style.
The important thing to realize is that there are two ways of writing narration : the scene and the summary.
A scene is when you describe a series of detailed actions in real time (and only pause it for long descriptions). "Rebecca took a seat at the bar, poured herself a cup of juice, and took a sip."
A summary is when you describe a series of events in a general manner and over the course of a large span of time. "Rebecca spent some time at the bar to cool her head, then went straight to bed, and woke up at 8 am."
You can use one or a mix of both in the same journal as you want, but the more you use the scene, the more chance you have of going over the limit.
Scenes may seem cooler and more elaborate, but under a limit, they are actually much less efficient than the summaries when it comes to transmitting various and numerous information. A scene spends a lot of words to say only a few things in the end. A summary is much more quick and direct about what it tells about, and very flexible (you can easily jump from a topic to another, and even tell the events in an non-chronological order like I do sometimes). Under the character limit, what I do and recommend is to prioritize the summary, and only use the scene scarcely, for the action-packed mission reports, or very specific and short moments (including dialogues) you want to give a special focus to.