Chromecast was an endless source of frustration for me from having the first prototypes while at Google, to the latest devices.
It solves such a simple problem that no one else seemed to want to tackle - put a video on the TV - and yet, it never quite worked reliably.
We used it every evening for years and 19/20 times it streams effortlessly and instantly... 1/20 times I'm restarting browsers, TV's, WiFi until we give up and watch on a laptop.
Back to the HDMI cable. In retrospect, I should have never left it.
We have 5 Chromecasts with Android TV and they all work perfectly. We really only use Plex, Youtube, Netflix and a few other streaming apps, but none of them has any problems. It sounds like your problems with Chromecast are due to the rest of your network infrastructure and not the Chromecast.
We used it every evening for years and 19/20 times it streams effortlessly and instantly... 1/20 times I'm restarting browsers, TV's, WiFi until we give up and watch on a laptop.
Back to the HDMI cable. In retrospect, I should have never left it.