Ganon is rough for Kirby but it's not unwinnable, focus on staying as close as possible on Dorf, his upclose game is generally awful & that's where kirby excels, once you get in don't ever let him get away because then he outranges & outpowers Kirby pretty hard.
Wintermelon43
Quoting this because it's a perfect description of the matchup. It's a bad matchup for Kirby without a doubt, but it's not unwinnable (I'll admit I was exaggerating earlier). Whatever you do, do
not try to space Ganon out. Most characters will lose a spacing war to Ganon, and Kirby is going to lose particularly hard.
To go into a bit more detail, Ganon's primary spacing tools are D-tilt, Dash Attack, N-air, B-air, and a little bit of everything else. Ganondorf loves people to be in his Dash Attack/D-tilt range (about 1/4 FD) where other people can't reach him but he can threaten people with his long range and burst movement. At the same time, Ganondorf has a terrible grab, jab and a F7 jumpsquat meaning he has a lot of trouble once people get close. As a result, your goal is to be in close range as frequently as possible (but not in Ganon's grab range of course, which isn't very hard to avoid lol, just don't literally be on top of him).
My advice is to go into training with Ganondorf and Kirby and try to get an idea of how far away Ganondorf can hit you with various attacks. Use that spacing knowledge to look for openings, and once you get Ganon where you want him try to get as much damage as you can.
As for offstage, when Ganon is recovering be very careful about edgeguarding him. Unless he's in "I have to up-B
right now or I die" distance, edgeguarding him will not be easy or risk-free. His aerials all have big hitboxes and disjoint and it's really easy for him to beat out edgeguard attempts with them, especially against short-range small hitbox characters like Kirby. If he's forced to use Up-B though, go ham with D-air.
For recovering against 'Dorf, you always want to make the most of your multiple jumps, and try to avoid using Final Cutter as long as possible since it leaves you so vulnerable. Kirby's going to have to use airdodges a lot when recovering vs Ganon as none of his aerials are BEEF enough to complete with Ganon's.
edit: just noticed you asked for a matchup ratio, and I agree with my fellow Ganon's for the most part, though I think it's a bit worse for Kirby than they think. 60:40 at worst for Kirby, 55:45 at best. Rough matchup for the hero of Dreamland, but given Ganon's design you're probably going to win if you're the better player.