If you want to load multiple assets on the same path (like for ‘assets/level1/’), use Promise.all
this.load.setPath('assets/level1/')
await Promise.all([
asyncLoader(this.load.multiatlas('Level1_Atlas', 'Level1_Atlas.json')),
asyncLoader(this.load.multiatlas('Level1_BG_Atlas', 'Level1_BG_Atlas.json'))
])
I hope this helps