@automass You said in an earlier post that you suspect the charger because the dashcam switches off when the stop-start cuts in. When this happens, dashcam is still working while the engine is off, right? But it switches off when the engine starts is just highlighting a completely unrelated problem, and this is solely to do with your dashcam. When the engines starts, the starter motor is drawing several hundreds of amps from the battery, causing a momentary volt drop which the dashcam cannot accept and switches off. How old is the dashcam? I suspect that the internal battery, like the one in the photo has failed due to age, or it has a super capacitor to store power and has failed, or, you also said that it was only a cheap dashcam, so that means that it has neither of these inside to provide enough power to keep it running when the battery voltage drops, as it does when the starting the car up.
If it is the latter, then it has always done this, but you have never really noticed until now and because the car not starting is a massive problem to you, that your mind is looking for something to blame and has latched onto the dashcam and the charger which is providing the 5v power supply as being linked and the cause. When in reality they are a symptom of another problem exasperated by the low battery voltage while starting the car.
I got one of these 12v to 5v convertors that needs to be hardwired to a circuit that is only active while the ignition is on, so that means I have zero things left plugged into my 12v sockets which on Skoda's are alive 24/7, so when I stop the car and leave it, my dashcam and my TomTom satnav are automatically switched off, and cannot flatten the battery/