Does the EOS Remote app somehow support timed shutter speeds longer than 30 seconds or a press-and-lock feature when in
BULB mode? I've not found such a feature and I guess it could be absent so the (free) app won't compete with Canon's own expensive shutter releases.
As of now I need to keep pressing the button, and it would ruin the image if I have to press a lit display during the entire exposure. It's both very cumbersome and the light from the display affects the final image.