I don't think that the team working on the action game is the one that worked on Zelda. There were two recruitment pages by Monolith Soft in regards to the topic at hand.
1. The one recruiting for an action game that was outside of the studio's brand image from 2017 that's still up today.
モノリスソフトのブランドイメージとは異なる意欲的なプロジェクト。アクションゲーム開発経験者を募集しております。
www.monolithsoft.co.jp
2. The one recruiting for a Zelda (three months before TotK was revealed), which is also still up.
現在モノリスソフトが募集中の採用情報をご案内します。
www.monolithsoft.co.jp
The former may very well have been shelved, but I doubt these two projects could have overlapped, at least not to any significant degree.