It’s do-able for a long haul flight, but it’s a huge risk you’re taking. ATC may be trying to contact you and you won’t be able to respond to them. In the end, I believe that if you don’t have the time, don’t do a long haul flight. Tbh, I can see a lot of people doing long hauls in the beginning stages of global, but eventually, it will die down. For me, I will solely do short haul and medium haul flights, because they don’t take so long (1-3 hours). I will only do long hauls if I have a lot of free time, but again, I will only keep it under (8 hours). Some famous flight sim youtubers even say that they wouldn’t do long haul because it takes too long and there’s so much preparation to do for it.
In the end, long hauls can be done, but it’s not recommended to leave your device while you’re away somewhere.