Hi @aswin.manohar ,
It takes value in the same unit of your input geometry. If your geometry is in WGS84, the resolution is in degree. If your geometry is in UTM, the resolution is in meter.
The 2500 * 2500 pixels are the limit of the dimension for Processing API. The 1500 meter pixel resolution is the limit on how large a pixel can be depending on the data collection. The limit for the Sentinel-2 L2A data is 1500 meter per pixel in this case.
Yes, you’re right. You can use the Processing API until the dimension exceeds 2500*2500. Currently Batch Processing is only available with AWS, but there’s a future plan to add other cloud options. Please follow the thread here.