Shang-Chi did introduce us to Ta Lo.

I don’t think everything in this phase has to include multiverse. In the Infinity Saga, not everything directly involved the stones and Thanos.

In what world would it make sense for a 2016 Film in Black Widow to mention the Multiverse? It's a (Mostly) street Level Film that involves a character that is Dead when the Multiverse Saga is getting started. Why would Kang/RDJ's Doom/He Who Remains/Whoever even cared about Natasha and her family fighting against her personal abuser?

This is like saying that the Winter Solider or Civil War (Two of the Infinity Saga Most successful films I remind you) needed the Infinity Stones or Thanos. They didn't and Black Widow/Shang Chi/and Eternals didn't need the Multiverse.

There isn’t a need for Eternals need to connect to reference for the multiverse, not that type of story

Black Widow would really make no sense because that movie took place after Civil War

Shang-Chi didn’t need a reference either but it did tease the Rings to be important and it is sending out a signal to someone which could have tied it to Avengers 5 and 6