Currently the obvious tell is if they pitch Rust
I would amend that to "if they pitch any language".
The best language is almost universally "whatever we already use" or for new projects "whatever the team is most familiar with". It should occasionally be reconsidered, and definitely try out new languages, but actually switching to the new language after trying it out? That should be very very rare.
Technical Leads are not rational beings and lots of software is developed from an emotional stand point.
Engineering is trade offs, every technical decision you make has a pro/con.
What you should do is write out the core requirements/constraints.Then you weigh the choices to select the option that best meets it.
What actually happens is someone really likes X framework, Y programming language or Z methodology and so decides the solution and then looks for reasons to justify it.
Currently the obvious tell is if they pitch Rust. I am not saying Rust is bad, but you'll notice they will extoll the memory safety or performance and forget about the actual requirements of the project.
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