Realistically, there is no such thing as a wrong choice, only different tradeoffs. I assume "wrong" here means wishing you made different tradeoffs later on. But will you feel real consequences if that happens, or just a casual feeling of "I wish I'd have done it differently, but oh well" in passing?

> What limitations do either of them have when scaling?

What, specifically, are you trying to scale? What scale-related problems do your customers have?

Do you even have a product yet? If no, perhaps the best tradeoff you can make right now is the one that compels you to get started instead of worrying about it? Ask yourself: Will you be more apt to actually build it if you choose Go, Rust, or perhaps with another tool entirely? It doesn't matter if X is the unquestionably best choice if you never get around to using it.

You might still want to be mindful of what risk there may be. I expect you can tell me what risks there are if you chose Brainfuck, and I expect you would tell me that is a risk too great. But, without understanding your problem in depth to know what nuance needs to be considered, there is probably no meaningful risk difference between Rust and Go.