Finally got c6 Jahoda through the event, and the damage increase is pretty significant.
Take all things test dummy with a grain of salt tho since Jahoda needs to stick close to an enemy to get off her skill and that can be clunky.
Also my Jahoda is only level 71 with level 7 skill and level 6 burst. And she only has 11 cr, 92 cd. She does a non-insubstantial part of the team damage so there is even more room to grow.
Jahoda c6r2(elegy), columbina c0r1, flins c2r1, Ineffa c0r1
Sucrose c6r5(etherlight)
Edit: I did some more tests with r2 evenstar and ttds on sucrose and r2 evenstar reached about 261k ttds 264k
I also did Jahoda with fav and that hit 234k
so c6 Jahoda with r2 elegy is a side grade. Definitely a higher cost side grade too. Regular c6 Jahoda is a noticeable downgrade. Not generally worth it to invest in but ok specific account contexts.