I just picked up a new M3 SR+, the reputational quality of Tesla is outdated. Their initial Model3 2017/2018 for sure had some early manufacturing issues, but following closely on various forums and subreddits shows that is behind them. A sample of just 1 (mine) isn't good enough to prove that for sure, but I can say all the doors, trim etc. is spot on for me.
With regards to the difference, the minimalist luxury design of the Tesla's is a step far above anything you'll get from Kia/Hyundai. I find the interior better than BMW, Mercedes, Audi etc. But that will be a personal preference, do you like tons of buttons and switches or minimalism.