Hal Leonard and Musescore

I am new in music but I just noticed that practically all the official musicsheets belong to Hal Leonard Co. This company was acquired in a merger with Muse Group in 2023. Muse Score is an app with 1.3 million sheets.

Muse Group is owned by people related to music, and even many that came from Hal Leonard by now.

I am a little concerned that all the scores is concentrated to one sole company and what it means for the long term future. Is there a way another company or group can also get hands on copyrighted sheets or is this a monopoly? Like let us say a malicious billionaire acquires Muse Score and closes shop...what happens? I find this concerning. Anyone can put me at ease?