You already have two good teams, so it doesn't matter as much who you pull for. Childe/Hu Tao/Ganyu are all good.

With Ganyu, you can run 2 permafreeze teams, or a melt team with her. She is also a very flexible dps with sub dps potential as well as the dps ceiling in the game.

Hu Tao is a straight upgrade to Yoimiya, on top of not needing Bennett, which frees him up for your other team (not necessarily Ayaka's, but in general). Dragon's bane does wonder for her.

Childe is a very good enabler, most often paired up with Xiangling (and Bennett) or Beidou (and Electro battery, mainly Fischl). His comp is an upgrade to your current Yoimiya comp as well, but you'll need to build Xiangling or Beidou for him.