I recall that Ergotec has some 12° back sweep bars.
BTW I use their "High Bass" stem which has 40mm of rise, as I think that most mtbs have too low handlebars, and that a higher handlebar is useful especially when you have a modern bike with long reach (and in my case also a high BB). My bike...
A friend of mine has the old version (SC4) on his Zeb. Really nice. But I don't think that they list compatibility with Suntour forks. You may ask though.
Actually I don't think I've ever seen a kit to upgrade a Suntour fork from some suspension tuner 🤷♂️