As a mirrorless photographer I use a lot of processing to create a unique look. If I at all can, I set the aperture really small, use denoising, sharpening and color grading. If people think my photo came out of an old book that’s great.
I have looked at various “film look” filters and so far haven’t found one I like. When I think “film grains” I think of irregular shaped crystals, but most of the fake film grain I’ve seen makes a square pixel grain which doesn’t convince me at all. My understanding is the grain already exists before the image is shot in the sense that the films has irregular “pixels” which respond more or less because of shot noise and variation of the grain and I haven’t found anything that really simulates this.