Honestly, if you're even slightly concerned about Go's memory footprint and optimization then you shouldn't bother digging any further into Ruby.
There's a reason that the DevOps world abandoned Ruby wholesale in the late 2010s (mostly replacing it with Go).
In a world where container orchestration allowed servers to be more fully utilised, it became increasingly obvious that the ancillary tooling (think log shipping or metrics collection) often had a larger memory and CPU footprint than the core service itself.
Formerly popular tools in this class like Sensu or fluentd have either been rewritten or replaced with Go equivalents, and Ruby seems to be more or less dead for new projects outside of the Rails niche.
I think how many quality devs you can hire with that language is really the only question that matters 90% of the time (ballparking), so long as the language is designed for that use case, like don't use assembly to write a production webapp.
I don't know many devs that code with Ruby, I know of more devs that code in rust and Go which are newer by at least a decade? so the question of what actual benefits it has is important.
For Go, it makes it hard to mess up error handling and easy to deploy your apps since it's all a static blob, but memory footprint and optimization can be challenging at times. For rust, it takes a long time to do things, so fast shipping timelines might not be a good fit. For Ruby, does it have anything that makes it more secure, faster to code with,resilient to failure, easier to scale,etc...? I don't think anyone answered that here.
What can it do _better_ that the other languages you listed can't or can't as well?