Apple Remote for my Smart TV without Apple TV hardware?

No, but you can use the Apple TV Remote widget in Control Center on your iPhone or iPad with an AirPlay 2-compatible smart TV.

Set up the Apple TV Remote on your iPhone, iPad, or iPod touch - Apple Support

No. However, the manufacturer of your smart TV may have an app available in the App Store.

That is impossible.

Yes.

U have 2 main models of Apple remotes, they are:

1- "Apple Remote" is an infrared only remote, it sends orders to your Apple TV and will send to most television screens as well.

On the television, the volume up and volume down buttons are usually the ones that work with your Apple Remote, even if your Apple TV device is off.

2- The newer "Siri Remote" has both, bluetooth and infrared. This remotes also can send orders to your television even if the Apple TV device is off. It sends volume up and down... and sometimes even powers up your television.

No you cannot do that.