I agree with the comments here. Personally, the sweetest coffee I have tasted is natural processed Kaffa Anderacha, which managed to keep some sort of cherry flavor no matter which roast level. I think you might get a real feel for sweetness in coffee with a quality natural processed coffee from Africa. The only issue here is that it was pretty tart, or sour\acidic, which, to my understanding can be alleviated by having it a little darker roasted, but that might also degrade the cherry taste.

I’m currently reading this. https://perfectdailygrind.com/2018/05/why-are-some-coffees-more-acidic-than-others-a-brew-roast-guide/

It might help you in deciding which green coffee you want and how to experiment with it. I hope it gives you ideas like it does for me, I’m currently experimenting with pan roasting. If you want to invest anyway, I’m not recommending you do many pan roasts but you might wanna try at least one, especially since it’s super cheap to accomplish.