We still own two Hyundais, and believe me, Hyundai is no Toyota.
The reason why they recommend 5W-30 is because those engines were never designed for lower viscosity oils, to begin with, so they tend to grenade when you run 0/5W-20 in them. Hyundai has improved things once they introduced MPI/GDI dual fuel injection. I can run 0W-20 safely in our 2020 Sonata, but when I had a 2018 2.4L Santa Fe, that thing would only see 0W-40, because on thinner oils it had a habit of chewing up its own bearings due to fuel dilution and other issues.
Considering current prices and market trends, we will not be buying another Hyundai, ever. There is always some surprise with their cars. Knock on wood, I took extra care of all of them to avoid running into issues, but that extra care is slowly getting on my nerves. I'd rather worry about other things.