> Here it seems Python's approach had too many drawbacks, considering they just added formatted templates t"..." that don't evaluate to a string.

That's not a fair characterization at all, since the plan was always to add something like the t"" strings. Having a version that immediately evaluates to a string is convenient, and adds very little complexity either at the implementation level or conceptually.

I don't think that was always the plan. Certainly the proposal has been tossed around for a while, but the overall historical evidence paints a different picture for me.