The requirements are:
- that data are in cloud optimized geotiff (COG), with each band in a single file.
- the internal tile size must be equal across all overview levels (including the full resolution source)
- the projection needs to be one of: WGS84 (EPSG:4326), WebMercator (EPGS:3857), or any UTM zone (EPSG:32601-32660, 32701-32760).
Bands can have different resolutions.