Cord cutter observation,

I'll condense this. I've used a ROKU stick fora couple years now. I pay my 6 bucks to ROKU every month, because there a few quirky channels i watch on the ROKU channel.My TV broke, so being a cord hater, I bought a ROKU TV.
Set up the TV, did my OTA scan, checked and all my apps still there.Figured out how to pull up OTA guide with new remote.
I was bored here, yesterday morning, and running through my OTA guide, and here' s the point.
My local stations through the channel scan, stops at digital channel51.4, which is correct. Figured if I hit the" down" button, one more time, it will cycle back to my lowest OTA channel.
Nope, it jumped to channel 115, and stopped at channel 670,or something like that. Obviously, this is the guide for ROKU channel, but it's a Guide! And the channels included, I'm watching NFL channel now, golf later.
They have , news,movies,cooking docu, music ,classic tv shows, etc.etc.
I'm just interested is other smart tvs, have this. This is my first smart TV, and I was awake, watching old shows I would haver found thru the ROKU home screen or app.
Maybe I'm missing something else about smart TVs?
I'll take hints here, ( it's a Hisense 40 inch.I got it for 198 dollars)
Thanks,
Koz