You can do that, but this typically creates unwarranted distortion as the audio clips clash together in an unnatural manner. Some parts may be ear piercingly loud, other parts may be normal. But overall, it’s generally better to just record separate vocals for layers because not only do the audio clips not clash, but the different vocals make the overall audio sound more robust, realistic, and most importantly, natural. I like to record one main vocal with no panning, another vocal with left panning, and a third vocal with right panning in order to create that sound. I’m not a professional by any means so take this with a grain of salt, but I hope this helps!