I've tried a bunch of web browser apps, and it doesn't seem like any of them work. None of them seem to load a webpage or play a video on a webpage.
Do I really need to connect a tablet to my TV with HDMI, and open a webpage or play a video on the webpage on the tablet?
Tvbro on github
Try web video caster. I use it to stream live sports and highlights to my firestick and 2017 shield. Works really well for me. Hope it works on the websites you use.
Quick guide if you need it: get it from the play store or mobilism for the premium version.
When you navigate to the web page with the video/stream, it'll scrape for the file(s) and show a play sign in the top right corner.
Make sure you're connected to your Chromecast. Click the play sign in the top right corner, select the file/stream you want and it should play on your TV.
Puffin is best with CCWGTV remote
I use TVBro, it's basic but straight forward and works.
Puffin TV browser. Give it a try.
On the Shield I did sideload Chrome and it works fine. It's an android OS after all.
Would help to know what you tried, but I've used Opera on Android TVs (Nvidia Shield TV, FireTV Stick, etc.) without an issue and was able to play back videos and live streams.
try jiopages