What exactly would i need to record a good cover video for youtube?

Cameras generally use analog microphones - 3.5mm or occasionally XLR types for professional gear.

However, the noise levels and audio quality are not necessarily all that good when using internal audio, especially if the camera is being moved around.

The cheapest way to get good audio for a straightforward video recording is to use a totally separate little digital audio recorder with a good external mic connected to it.

You then sync the separate video and audio files using some video editor program.

For a music recording, it depends if you are happy with all the audio - vocals and any instruments - being on the same recorded track. If you want to keep instruments and vocals separate, you need a multi-track DAW to get the best results.

If you are using a backing track you can import that and play it through headphones while you sing along to it, either recording the audio to another track on the DAW (using an interface) or recording it separately and then importing & syncing that.

You can repeat the whole thing to add extra vocal or instrument tracks.

That all allows you to adjust individual track levels and equalisation or add effects, reverb etc. as needed before exporting the whole thing as a new file to combine with the video.

T6 is an excellent free DAW if you need one.

https://www.tracktion.com/products/t6-daw

When it comes to video quality, DSLRs are no longer needed, and you might be able to film on your phone or a simpler camera. Once you choose the device, you need to choose the right microphone. Most DSLRs use a 3.5 mm mini-plug.

You might also need to invest in a tripod to keep your camera stable.

If the mic is connected to the camera and everything goes as planned, you do not need any special software, unless you decide that you will want to be editing.

Good luck!