Corviknight has great utility, which is more useful in competitive, while Togekiss has more coverage options. But let’s look at how the typing matches up in Galar:
Corviknight can do well against: Milo; Kabu’s Centiskorch; Bea; Opal; Gordie; Piers’s Scrafty and Skuntank (to an extent); Raihan’s Gigalith; Marnie’s Scrafty Toxicroak and Grimmsnarl; Hop’s Trevenant and Rillaboom (if you chose Cinderace); Bede’s fairies; Oleana’s Froslass, Tsareena and Garbodor and Leon’s Mr. Rime (if you chose Cinderace), Rhyperior (if you chose Inteleon) and Rillaboom (if you chose Inteleon).
Togekiss can do well against: (I will start at Kabu because that’s when you can get Togepi and have evolved it into Togetic) Kabu’s Centiskorch; Bea; Piers; Raihan’s weirdly limited number of dragons; Marnie; Hop’s Trevenant and Rillaboom (if you chose Cinderace); Oleana’s Tsareena and Leon’s Dragapult, Haxorus and Rillaboom (if you chose Inteleon).
So as you can see, Corviknight does better when partnered with Cinderace or Rillaboom, while Togekiss does better with Inteleon. However, I would still say go for Corviknight with any of the starters because of its access to U-Turn, allowing you to pivot if the matchup isn’t good. Also, it’s the fastest new steel type, and the steel type destroys Galar.
A moveset:
Corviknight@Leftovers (found in Giant’s Seat)
Ability: it doesn’t really matter but try to get Pressure since it’s not useless
Iron Head (TR) / Steel Wing (move relearner)
Brave Bird (level 50) / Drill Peck (level 34)
Bulk Up (TR) / Body Press (TR)
U-Turn (TM found in Glimwood Tangle)
Just go with whatever you get first on the Bulk Up/Body Press. As for the others, it’s your choice.
And one for Togekiss (thanks Y):
Togekiss@ExpertBelt (found in Turffield after you solve the riddle)
Ability: Try to get Serene Grace
Dazzling Gleam (TR)
Air Slash (evolution)
Aura Sphere (move relearner)
Shadow Ball (TR)
Hope I helped!