I’m using <ion-item routerLink="/">, which seems to be working
And while this is working in Vue, I don’t see it documented in the types
Is this expected?
I think it is just undocumented as it definitely does work. The only references I can find are being defined here and used here. No idea how it gets wired up 
As a side note, you should be using kebab-casing for props in your template router-link instead of routerLink - Vue source.