I kept a dream journal for a couple of years.
Subjectively there was no way for me to know if it was memory or just my tired brain making a story out of the left over bits of sleep.
It did fuel a lot of creative writing though (both in and out of the journal). And helped me be more in touch with my emotions.
Also kept a dream journal.
The trick is not to focus on the story (what the dream is about or means) and to recall the emotional energy in the dream.
Learning to meditate and tune into my emotions was both aided by dream journaling, and an aid to dream journaling.
Plus the emotional content probably has more meaning than whatever story you’re telling yourself.