The perception of Kia as an unreliable brand has been enduring since they earned it in the 90s.
I know a few people who own a Kia Soul and they generally have no issues with it in terms of reliability. One is a loaded 2013 with almost 100k and it has been particularly bulletproof, just regular maintenance, looks like it's only 2 years old in terms of wear. My father in law has a 2007 Santa Fe (a Hyundai, but they own Kia) that has been very reliable. These are anecdotal but the data also seems to show that Kia has become very reliable
2019 reliability survey (whatcar.com). Kia/Hyundai seems to have made very steady progress over the last two decades in terms of reliability, along with the warranty I no longer have any reservations about buying a Kia. I wonder how much longer they will offer a 10 year powertrain warranty, they may not have to offer it for much longer.
I don't know how reliable the Telluride will be but considering how hard Kia has worked to shed the reputation of being unreliable I seriously doubt they would allow their new flagship vehicle in one of the most profitable categories (midsize SUV) to undo all of their work. It would only take a few headlines about class action lawsuits for people who bought 40-50k Kias to send the brand's reputation back down the drain. I'll put my money on Kia being smart enough to put the work in to make the Telly hold up. I've only ever purchased Honda & Toyota, kept them all past 200k, I really care about reliability, now I'm buying a Telly.
Also keep in mind that cars in general have gotten wildly more reliable than in the past despite increasing complexity. It wasn't that long ago that cars would regularly not startup and people carried on with them for years, now if a car doesn't startup and it wasn't user error (dead battery) most people will start looking for something new. Most car brands are pretty close in reliability, there are really only a few that still have major issues across most of their models and Kia is NOT in that group.