To which level can an antecedent of "which" be a phrasal noun? Can an entire clause be the antecedent? [duplicate]

I see many answers on the antecedent of "which", but not with this level of detail. In this sentence:

The values of MAE and RMSE obtained for the validation phase are similar, which confirms the method is robust.

Is the sentence correct? If yes, is the phrasal noun the entire first clause "Values of MAE and RMSE obtained for the validation phase are similar"? Or is the meaning of "which" more like "which fact", with "fact" understood?

Basically: To which level can an antecedent of "which" be a phrasal noun (i.e. a set of more words)?

The values of MAE and RMSE obtained for the validation phase are similar, which confirms the method is robust.

Preliminary point: non-defining relative clauses allow virtually any expression as antecedent; not just NPs but other phrases, as well as clauses, and even whole sentences.

The antecedent of "which" is the preceding clause "The values of MAE and RMSE obtained for the validation phase are similar".

We understand that R confirms the method is robust, where R is interpreted as "The similarity of the values of MAE and RMSE obtained for validation".

Note that I've nominalised the interpretation of the antecedent clause, which is perhaps what you meant by 'phrasal noun'?