One way to look at your choice is to ask which path will expose you to the most new ideas.
If you're already proficient in one or more procedural programming languages then certainly Rust training will fine-tune your skills. OTOH if you have no procedural programming skills then Rust (or C et al) would be a good place to start if you want to learn to program.
To study machine learning is a completely different endeavor that (gracefully) begins with high-school level math (algebra, matrices, linear algebra) and ends at a research frontier where, to all appearances, no one fully understands what they're doing, but are convinced it works! And since demand is endless, "there's gold in them thar hills!"
I vote for ML but take your time and don't get lost searching for gold in the hills. Maybe look for side-opportunities as did Levi Strauss:
If you're already proficient in one or more procedural programming languages then certainly Rust training will fine-tune your skills. OTOH if you have no procedural programming skills then Rust (or C et al) would be a good place to start if you want to learn to program.
To study machine learning is a completely different endeavor that (gracefully) begins with high-school level math (algebra, matrices, linear algebra) and ends at a research frontier where, to all appearances, no one fully understands what they're doing, but are convinced it works! And since demand is endless, "there's gold in them thar hills!"
I vote for ML but take your time and don't get lost searching for gold in the hills. Maybe look for side-opportunities as did Levi Strauss:
https://www.thoughtco.com/levi-strauss-1992452
https://duckduckgo.com/?q=levi+strauss+gold+rush