I have the M1 macbook Pro and I am using AppleTv can use my Mac to connect it to a smart TV?

You sure can !!! I believe your m1 MacBook pro has USB-C ports on it (Thunderbolt 3), so you'd need a USB-C to HDMI cable.....or, even easier than that, Apple TV has Airplay built into it, as does your M1 MacBook pro, so all you have to do is make sure both your m1 MacBook Pro and your Apple TV are on the same Wifi network, then Airplay your stuff to the Apple TV, and from there, it goes right to your TV..... no cable needed.....You'd also have to make sure on the Apple TV box, that your m1 MacBook Pro is chosen as the source for your Airplaying.... then away you go....chooose Airplay when playing a movie as a video output, and it should come up on whatever hdmi input your Apple TV box is set on on your smart TV.....

that's the idea, anyways

John B

When you connect an external display or TV set on a cable to your Mac, it becomes a display for your computer. There is no magical relationship going on here.

If you use the smart TV to make the connection as it it were an Apple-TV DEVICE over Wi-Fi, that is slightly different, but you are mostly just eliminating the cable.

The magical part is when you pull in the content directly into the Apple-TV device or equivalent, and can store it, share it, watch it -- all from that other device.

sure, i don’t see why not… your external is plugged into your mac, the downloaded movies are on there, so as long as you point Airplay to your external and to your mac, you should be good to go