Based off your country, your broadcast technology is the same as china's DTMB.
Most USB tuners are DVB or ATSC due to them being the most common.
I also do not think google bothered expanding support for usb tuners, only a few work and most are ATSC.
most people buy a HDHomerun but I dont know if they have DTMB ones.
Best option in my opinion is buying a raspberry pi or similar, adding a DTMB tuner, and figuring out some software to stream as m3u, then playing it on the tv through an iptv app, which is complicated and may not be powerful and smooth.
So this is my first post to this sub reddit
A little detail
I live in Pakistan and we here use PAL B VHF/UHF signal for our cable TV, I am using our old Sony trinitron KV-AW21M80 21" TV connected to a chromecast, I want to use the built in TV tuner on it (I would like it to work on the android tv google live channels app)
How can I do it, and can I do it with a flat screen TV
Ypdate I also posted this on r/crtgaming and r/googlehome
Looks like you have it working, but are you hoping with a different setup you will get a better picture? Or just so you can connect another device at the same time?
I don't have any experience with this, but I would imagine the only way to do it is if there is some adapter you can buy that goes from HDMI to coax. Like I said, I don't know if this exists (quick look on Amazon and it seems there might be some options, again, I have no idea how good they will be).
The way you connect it won't make a difference in what apps you use, and it makes no difference that a TV has a flat screen or not.
Again, I am guessing here, but if you are hoping that you can connect the CC to the TV Tuner to be able to get channels, that's not how it works. CCs only work with an Internet connection.
Download Pluto tv. It allows watching TV programs
You need much more masking tape. Try using some tin foil as well.