I have been doing a one-line-a-day journal for the past two years. If I ever feel like writing more I have a separate section for that, but I only ever tell myself to write the one line. It's the first time I have been able to consistently write in a journal for a very long time before I started. My entries are not nearly as "composed" as the examples here, though, just tiny highlights of what happened during the day.
Is the point of journalling for you to have memories to look back on or to help you process what happened during the day or another reason? (I've never tried it so I'm trying to understand the purpose.)
A pattern that tends to stay sustainable: first sentence is purely factual (what happened), second sentence is directional (what to adjust tomorrow). Still short, but much easier to use when you reread older notes.
Another approach to journal writing is basically the opposite: rather than treating it like a task to fill with very rigid requirements - find a notebook and pen that you'll enjoy spending time with. An easy start is a Midori Ruled A5 (very simple, lay flat notebook) and a Uniball Zento Signature (the most hyped pen in the world right now) and treat them basically like little friends you spend time with. Writing only two sentences is denying yourself quality time writing and reflecting at a leisurely pace if you really come to enjoy it.
I'd also think you're more likely to read back if writing time is a fond memory.
[0] https://www.leuchtturm1917.com/some-lines-a-day.html
I'd also think you're more likely to read back if writing time is a fond memory.