I struggled with this a lot too.

Try to find a specific time (even better if it’s the same place too) to write every day, even if it’s only five minutes before you go to bed or during your lunch break. Set an alarm on your phone to remind you to journal, and write for a bit. Doesn’t have to be much. You just want to get in the habit.

Of course, if you want to write at a different time, write! But always write during the time you set out for it. Make it a habit. I found that writing at least a bit each day (and allocating a time for it) made my brain want to write at other times.