This question already has an answer here:
Prior to the Battle of Scarif,
Bail Organa informed Mon Mothma that they will need every edge they can get against the inevitable confrontation against the Death Star. Mon Mothma caught on that Bail was probably planning to seek out his "Jedi friend". She appeared not to know it to be Obi-Wan, let alone that Bail actually had two surviving Jedi friends.
So the question: In light of the magnitude of the situation, why did the Rebellion seek the aid of only Obi-Wan but not also Yoda when they need every advantage they can get to destroy the Death Star?
Arguably, a superweapon like the Death Star would be an issue grave enough to force Yoda out of exile if his aid had been sought to save the galaxy, in my personal opinion.