Yet another argument against sunsetting ATSC 1.0

I just upgraded from a cheap $20 indoor antenna to a Televes V Zenit Mix in the attic. I already had strong signals with most channels with the cheap antenna, but if the 9 ATSC 3.0 channels it picked up, only 3 or 4 of them would maintain a stable enough picture to watch an entire program without frustration. Now my Televes of course solved this problem, but look what happens when I try to split screen any of them with my Chromecast. Image one shows the message I get that NextGen channel can't be watched in multi view.

IDK if this is a broadcaster setting, or if it's a resource issue with the TV. It's a Samsung QN85, so it's no budget model display. Image 2 shows that ATSC 1.0 broadcasts work just fine in this setup.

Anyways, I just thought I'd share my rant with this community since I found it to be hogwash. None of the NextGen channels in my market are broadcasting anything in 4k, but the audio quality is far better than their ATSC 1 counterparts. If the FCC allows broadcasters to end their 1.0 broadcasts, this feature of the TV just won't work anymore with the TV tuner as one of the sources in multi view.