I received a sun shade from WeatherTech this weekend. It fits great, is light, and rolls up pretty easily. That's been my experience with their sun shades in the past. As for cargo mats, I haven't gotten a cargo mat from them in 20 years, but that one fit and worked great. Can't speak to the one from Kia.
I purchased the "Lloyd Northridge Standard Cargo Mat" from CARiD.com and I love it. It is custom fit for my 2018 Niro PHEV and completely solved my problem with my weekly case of wine purchase sliding from one side of the cargo area to the other, with every turn on the drive home!
I paid $99.90 with free shipping, which was cheaper than what I found from WeatherTech. Like any rubber/plastic/vinyl product, it took a few days for the "chemically" smell to dissipate, but I am completely satisfied with that purchase.
I think WeatherTech may be your only source for a custom fitted window screen, and you can buy a kit for all windows, not just the front. On the site, it shows them all snapping into place. That is custom fitted and cool!
Expensive though, the front alone is 4 to 5 times the cost of a generic in an auto parts store.
I am using the cheap sunshade from Walmart that has two panels with springy frames that you twist to collapse. The springy edges create enough tension against the A-pillars and the rear view mirror that I don’t need to flip the sun visors down or suction cup them to the glass. Not the fanciest looking thing, but gets the job done.