chapotraphouse

and yes i have tried dream journals, but you need to remember something to write it down. i could write 'i maybe had a dream about a house at night or something, there was a window and lights' and that would be like 99% of my dream journal entries

This is normal for beginning to dream journal. Making entries like that is perfect. I do not know exactly how it works in the brain but I know from my own experience and others that if you consistently write down the little bits you do remember, your brain will gradually start retaining more.

i keep waking up in the middle of the night, not enough to do anything (if i really 'got up' even enough to jot down notes, i wouldn't be able to get back to sleep), saying to myself 'i definitely was just dreaming, i'll definitely remember this well enough in the morning to write it down' and then its gone by the time i'm actually awake

This also happened to me during this process and I think it's an important part. What I did was keep a scratch pad next to my bed. Wake up, do not turn on the lights or move much at all, and just scribble down something illegible. Alternatively turn on your voice recording app and mumble some nonsense. Go back to sleep as soon as your body wants to. It doesn't matter that in the morning you don't understand what you said or wrote. It's something about your brain being shown that it's important information to retain.

I use weed for PTSD too, and it definitely makes remembering dreams more difficult because you just don't have as many with the REM suppression. But since I've made a practice of dream journaling - you really do have to keep at it unfortunately - I still regularly have the sort of "meaningful psychodrama" dreams that I end up discussing in therapy and dissecting to better understand my own feelings.