I was thinking of this too.
I'm absolutely sure there are methods of live streaming using open source or other live stream or just standard webcamming apps. Telegram maybe I don't know. A few problems that come to mind are telemetry - if you're streaming from your phone in a pre announced event, there is obviously going to be somebody lurking or reporting it LE increasing the risk of geolocatiom and rescue.
There are certain methods that are readily available, peacefully painless and highly effective that if broadcasted could create undue attention and ruin those methods by way of heightened scrutiny and restricted action. Three principal one that comes to mind is the liquid nitrogen purge in a confined space or vehicle cabin (similar to inert gas asphyxiation less the complex apparatuses, brain dead proof and cheaper advantageous where LN2 is freely available without restrictions such as the US but much more prohibitive in the UK), creating a possible cascade effect of regulatory fallouts or heightened scrutiny and killing the deal on the method by way of excess media or regulatory exposure.
Anything that draws attention to yourself or whereabouts wether pre-announced or not in the commission of an act of suicide is a confounding variable that increases risk one way or the other, or just adds an extra element of complexity and logistics. It also creates proof or evidence that you do not want prejudicing yourself later in the event that you survive because it will be irrefutable evidence that if you survive, may cause you to become sectioned depending on jurisdiction and lose your freedom and liberty and right to free agency in autonomy in do-overs.
If there would be an advantage or is done in the name of science then you would have to use a burner phone with a GPS spoofing app or webcam that can't be tied back to you with some way of obfuscating your identity. Depending on jurisdiction what you say in the video could or could not come back to haunt you in a legal or psychiatric lockdown situation.
What would be the objective? Is it worth it added logistics and complexity? Is it worth the benefit over the risks or drawbacks? It could or it could not. Very case specific.