The reason I believe this is such a good fight is that Yoda stalemated Darth Sidious over-all despite being two decades away from his natural death.
Luke Skywalker with an amplification by Leia and fetal Anakin defeated Darth Sidious in the Emperor's most powerful incarnation before becoming far more powerful as Jedi Grand Master.
Right, but I don't believe that reversing Yoda's infirmities would have made up for Sidious studying sources of knowledge from over a million worlds, and becoming so powerful that he could literally distort the space-time continuum and was in fact affecting it with his mere presence. Sidious ultimately became more of an energy being than a living being.
Being more than two decades away from your deathbed doesn't make you weaker, lmao.
Naturally, a younger Yoda wouldn't have to depend on Force augmentation as much, but every Force user depends on it regardless and Yoda's power/connection to the Force would've likely increased over two centuries so he could more than make up for faltering age. If Dooku, Bane, Krayt and many others can do it, then someone considerably more powerful than them can do it as well.