People training RL policies for real robots — what’s the most painful part of your pipeline?

Hey,

I’ve been going down the rabbit hole of sim-to-real RL and I’m trying to understand where the ACTUAL bottlenecks are for people doing this in practice (not just in papers).

From what I’ve read, domain randomization and system identification help close the gap, but it seems like there’s still a lot of pain around rare/adversarial scenarios that you can’t really plan for in sim.

For those of you actually deploying RL policies on physical robots:

1. What part of your workflow takes the most time or money? Is it data collection, sim setup, reward shaping, or something else entirely?
2. How do you handle edge cases before deployment? Do you just hope domain randomization covers it, or do you have a more systematic approach?
3. What’s the biggest limitation of whatever sim stack you’re using right now (Isaac, MuJoCo, etc.)?

I’m exploring this area for a potential research direction so any real-world perspective would be super valuable. Not looking for textbook answers — more interested in the stuff that’s annoying but nobody writes papers about.