Not a pro, so just voicing an opinion here. You said subtle changes, but the charcoal headboard seems like a big departure from the rest of your furniture. I wouldn't combine that headboard with your existing footboard and night stands. Nor would I upholster the two existing pieces, because my read is that the pine furniture is more rustic than tufted upholstery would call for.

Would you think about painting the furniture to get a new look?

I’d probably contemplate a new set before painting

I agree a new bed for sure I can’t see that foot board working with the gray headboard at all.

Believe it or not, I actually painted the fabric portion of a headboard fairly within the past 5 years. I did you paint specifically for fabric. I applied several coats of several different colors of paint using a stencil brush and wound up with a really nice (if I say so myself) leather look. That might be a way for you to get the color you want without having to replace either the headboard, footboard or both. If you are interested, let me know and I will take a photo of it and post here. BTW, the paint job, like I said, is about 5 years old and it has held up wonderfully.

I'm definitely realizing that headboard won't work. Our furniture is of good quality and we live in a 1918 craftsman style bungalow so it goes because it actually has that Spanish mission type of look, the hinges and hardware add to that. i wouldn't be opposed to just swapping the bed out, but I'd have to find something that would go with the furniture. I started looking at new furniture online, but the Joanna Gaines style definitely dominates right now. I don't hate it, but I feel it's become somewhat overdone right now. Looking at this bed or something like it as a possible.

You might try searching "headboard" in Stories in the Houzz search field. There are quite a few stories linked with creative ideas. Maybe you'll see something there that you like and would work with your existing bed. Good luck!