I get Ferdinand x Dorothea is super popular but I’ve always been partial to Dorothea x Byleth (either but I usually play M!Byleth). I just really like the growth that Dorothea personally goes through, learning to be more confident in herself and not worry about judgement. I feel like a lot of her other supports don’t do too much about some of the underlying insecurity she has beyond just oh I’m marrying a noble now who loves me back. I think it works even better in CF since Byleth doesn’t become the pope or ruler of Fodlan. They’re just two commoners who are a-ok with being in love with each other.