If you are using the teleport option then Alyx shouldn't really be making you sick in my opinion unless you are really sensitive.... So in that case I think it suggests there is something else wrong like bad frame rates or latency.
You are playing on the Quest I see from the 2hr battery life comment - is that via link cable or wifi? If the latter it would be well worth checking what latency you are getting as that could have a significant impact on nausea if your setup isn't on point. If the latency is ok, what frame rate are you getting? Try the 90hz mode if you can as 72hz may be contributing to the nausea. You could also download fpsVR which is useful for checking performance in VR games.
If you are using smooth locomotion then as others have said it's a question of building up tolerance which is achieved not by pushing through but by stopping early and building up to longer sessions. Also remember you can turn in real life, often more comfortable than yawing with the stick.
Anyway, whatever the cause it does go away for the majority of people. I never got nausea but I did get some really odd disconnected feelings especially with yawing in FPS games... now anything can happen, low frames, whatever and it has no effect on me. Keep going, but don't push through any sickness as it'll just end up worse.