Yes, all boxes you can install a browser and watch stuff on the browser. Performance depends on the app and the box bought.

Sybertv is as reliable as they want to be reliable. Can work for the next decade or shutdown tomorrow.. You don’t have a say and your money is burnt.

Tanix boxes have different models.. Each model may or may not be enough for your purposes.

FYI...your questions are akin to asking..” If I buy a Perodua car, can I install tyres on it and still drive on the road?” Or “is a myvi enough car?” .... Hard to know if one doesn’t offer more information.

Hey.. No need to apologize... We all learning here. Your earlier post only needed a little more clarity for a better response. Yeah, you can side-load many apps on to the Mi TV Stick or the Mibox or other Android TV boxes. However, just because one can install an app on a particular device, doesn't mean that it'll run the best on it. Think of it like games on PCs or Macs. Certain games have specific minimum requirements and will only run if one has those minimum hardware and software requirements. But even then, the difference between why a PC can run a game at 720p@30FPS max and another can run at 4K@120FPS, is the price. Often the phrase "Cheap thing no good, good thing no cheap" does apply here. The MiBox is much better than the Stick and that's why the pricing is different. For starters The same goes for other models' boxes. Doesn't always mean though that the most expensive is always the best choice for you either. Here's a quick list of differences between the Mi TV Stick & the Mi Box S 4K;

*Both have the same 8GB eMMC ROM, but the Stick only has 1GB DDR3 RAM vs 2GB DDR3 RAM on the Box.
*Maximum Resolution: 1080p@60FPS on the Stick VS 4K@60FPS on the Box... This is a major difference especially if you own a 4K display and would like to watch content in full 4K glory. No HDR on either though..AFAIK.
*Ports: Increased connectivity with the Box such as HDMI2.0a x 1, USB2.0 x 1, & Audio Out x 1.
From the above, I hope it is now easier to see that the Box is the better option between the 2. But ofcourse, I do encourage you to explore other options, especially if certified Netflix support isn't on your wishlist.

So regarding Syber TV. Unlike some "ehem" services which restrict usage outside their own hardware, Syber TV service allows their app to be installed and run on pretty much any compatible Android OS device. However, it is still up to you to have a fast & stable network. Preferably wired over wireless. The performance will still depend on the chosen box. So best to go with known brands than some no-name brand. Personally, I haven't tested Syber TV on any of the boxes I've reviewed, but I don't think they should have any issues. Perhaps sometime next week I'll try it out on my primary driver - the Beelink GS-King X, and report back. In the meantime, you can check my signature for links to my reviewed boxes, to see what boxes are capable of... I've got videos as well.. Give you a clearer image of exactly what can be done and what can't between boxes. Enjoy!