But i find it stupid that he lost his mojo in the first place however. Did I miss something? Has hiding from the inquisitors actively made him rusty?
Many skills atrophy surprisingly quickly with disuse, and it would seem that Obi-Wan has been quite actively avoiding using his. By the time of ANH, there's no gravity-defying shenanigans or moving objects around — a couple of "Jedi mind tricks" and that's pretty much your lot, so I don't have any particular problem with the level of power he's demonstrating here.
SPOILERS FOR THE REBELS ANIMATED SERIES
in the (great) Twin Suns episode, the Guinness Kenobi faces off against Darth Maul for the last time…..and gets in one lethal lightsabre blow before Maul can even react. The old geezer is definitely a Jedi Master at the top of his game.
That episode was written by Dave Fiiloni, whose fingerprints are all over the Kenobi show, and Feloni’s a huuuuge continuity guy, so you’ve got to assume the two things are still going to join up.