It varies a little with the Switch as with lighter games and low screen brightness you can get 6 or so hours but playing something like Zelda BOTW you get around 3 hours max before needing to recharge.
I find it interesting we’re still in that 3-4 hour battery life space thirties years later. I guess it makes sense as most people will want/need a small break after 3 hours with a handheld so gives you some time to charge it so I expect Nintendo aim for that 3 hour minimum.
The switch has much better battery life than that in the models released after the initial launch. You're spot on with the release model, though.
[0] https://www.techradar.com/news/the-updated-nintendo-switch-b...
This can sometimes be rectified by just dumping 5v into the battery for about 30 seconds, bringing its voltage up high enough for the controller to do its job.
The Switch seems to have exceptionally dumb power state situations it can find itself in. That is not just limited to the Switch, but apparently the power adapter has its own issues and needs to be unplugged for at least 30 seconds to be reset if it too enters into a faulty state.
You can attempt the right voodoo incantations with your switch:
1. Don't use the dock for any of this process.
2. Unplug the PSU from the wall for 1 minute or more.
3. Hard reset the switch by holding the power button for 12 seconds.
4. Plug the PSU into the switch and let it sit over night.
5. Repeat step 3.
If that doesn't work and nothing else is damaged, you get to take out about 20 screws to get to the battery and either replace it, or jump start it to revive it.
Seriously, very cool of you.