>>4029553You ask for a lot. You want the perfect camera. You said you want 1 lens. I'm guessing you want a capable zoom. Micro 4/3 would be perfect if it weren't for the low light. People are going to say oh just get the 17mm f1.2 bro and you can shoot in the dark bro, which is a $1300 lens by the way. You only want to use 1 lens, so that means a capable zoom. Forget about it.
First thing that comes to mind is the Lumix S5 with the 20-60 kit lens it comes with. It's all weather sealed and pannys are pretty tough. It's not the fastest lens, but the iso performance of full frame makes up for it. One small problem, the autofocus is okay for everything other than vlogging. You can make it work for that, just dont expect sony tier tracking. Its on sale right now for $1800.
Sonys are pretty cool for low light video too, some like the A7Siii are several stops better than the S5 in super low light but Im guessing that's out of your budget. The A7III is about the same as the panny but the 28-70 kit lens is considerably narrower than the 20-60. Also, theyre not as rugged as an S5. In no way are they up to being tossed around in a backpack while biking but thats just my opinion. Theyre not as weather sealed either, just moisture resistant, so you cant shoot with them in the rain.
