I doubt you’ll ever know how many times it’s been launched. The only way to check would be for a Kia mechanic to run a diagnostic on the onboard computer, that’s assuming it stores that sort of data and they’re prepared to tell you which they probably won’t.
As for what to keep an eye out for it’s the same as buying any other car, panel damage, rattles/knocks, have a look at the undercarriage see if it’s scrapped etc. Make sure it’s an actual 2019, look for the build date which is under the bonnet, and the inclusions, interior
ambient lighting, stainless steel scuff plates in the boot, bezel less screen in the front, Michelin Pilot Sport 4 tyres.
It might have been flogged, it might not have been, you’ll never really know.
If the deal offered suits you and your budget then do what makes you happy, whether it’s new or used as always when buying a car or anything really, caveat emptor (buyer beware)