Replying to Advice on prime lenses

So just throwing this question out there.

I currently have a 28-70 and a 70-300 but want to invest in a prime lens for low light situations/sharper quality. I shoot a lot of video and my photography isn't limited to one particular genre.

Judging from my lenses, what focal length would you recommend? I am leaning towards a 35mm because I like to shoot landscapes and I find it to have a more dynamic look than a 50mm. However, i also am thinking of a 16 or 24mm since my current lenses don't go that wide and it would be good for glide cam/landscapes. Open to any suggestions. Thanks