If you have an existing Mapbox GL JS application, it is easy to update your application to use MapLibre GL JS. In most cases you can simply replace the JS and CSS references.
You can use the ArcGIS basemap styles service styles to provide the basemap for your application. There are over 30 different styles to choose from such as streets, navigation, light gray, dark gray, OpenStreetMap, and satellite imagery. You can also create and use your own custom basemap styles by using the Vector tile style editor.