I would say launches.

'kick off' is informal and also means to start a football match 'launch' more formal

They are similar but when it comes to this digital example launches is far superior.

Yes they have similar meanings

Kick off the xyz promotion with great discounts. Kick off the baseball season, winning over xyz....kick off does mean launch or start something. Launch also means start something. I think kick off originally came from football the beginning of the game they kick the football. Launch is like to fire the rocket into space. I think it is all in the phrase you choose whether it sounds natural... sorry that’s my best non professional opinion..