My phone does timelapse photography. You set the delay time for a timer photo then set the mode to “continuous” (so it takes photos continuously until you press the button again). Let the camera take a couple of dozen photos then pick the one(s) you want to use.
I don’t know how standard this is across Android phones, but mine also has a voice activation mode. When set, saying “Photo” or “Snap” makes the camera app take a photo.
Also, you could buy one of these: