Why is Rust-based a feature? I don't care how your tool is built, I care for what it can do and how usable it is.

Google sucks and YouTube is evil.
If they were not such an explicitly and overtly shitty company, I'd pay for premium no qualms.
As it is, I wouldn't give them a dollar if the CEO would personally suck me off.

I'm just here to shill for Kotlin because, for non-performance critical applications (and notice I didn't say non-performant!), the JVM can still be an excellent platform.

And while Java still has many of its old 'faults' (a question of opinion, I suppose), it also has come a long way with many cool new features. But yeah, Kotlin really just hits it out of the park, I really want to encourage people to give it a try!

the whole language just feels more I don’t know how to phrase that… well/better-designed.

There is always Kotlin (and also Scala, if you want to go functional, that is).
It's a very productive and fun language with many great features over Java regarding null safety and other things.

I'd say Rust is only unquestionably best if you really need that last bit of native performance, otherwise, Kotlin might be worth considering as well for many use cases.