Assumably ’Ryan home’ is a production builder somewhere in the US? Is there some particular attribute of a Ryan home that should be taken into consideration regarding structural/exterior changes?

https://thelandofcolor.com/how-to-pick-roof-color-let-hue-family-be-your-guide/

The white "farmhouse" look is a trend that will date those houses in a few years. What color do you like? That should be your starting point.

I would also research whether a black roof will make your house hotter in summer.

Even my husband who is not architecturally educated can identify a Modern Farmhouse style house. It's such a specific style that as @cpartist says, it will end up being dated sooner rather than later. Mass produced subdivision colonials may not be special, but they are in a sense timeless in that millions of them have been built and millions of people happily live in them. A black metal roof strikes me as being very impractical. How long are you planning on living in this home? Anytime you make a non-standard design choice you risk alienating a large segment of buyers. Also, in order to completely execute the MF look you would have to replace your windows with black ones.

The trim around the front door can be changed to something less colonial and maybe since you're going to have a builder putting on an addition you could add a covered front porch. I hope you're using an architect for your addition. If so, ask them to spec out a front porch. Then you can side the house in a different color. Maybe DH would compromise on the roof (medium gray shingles are the most popular and versatile roofing choice) if you did white siding. Keep the black shutters - they add interest. You would then have a lot of choices for a front door color, or just use black if that's what DH likes. Good luck - it's always hard to get two people to agree on everything. :-)

I love metal roofs but not black usually unless going the MF look. . I think the addition needs to be shown to get some idea of what the house will look like with that added . You should have so drawings from the architect showing the new house with addition . Post that here right now there is no way to help. I have no idea what a Ryan house is so maybe explain that .