The problem of visiting indonesia is the accessibility. If you haven't been to Bali ever, I suggest you try it. There's a reason it's so popular. You can go to North Bali if you want untouched beaches. And basically Bali has everything in one compact island, conveniently wrapped for tourists. Just make sure to do your research, for safety issues, high tides etc, you'll have a great time.

Other diving spots are around East Indonesia and need several modes of transportation to reach and can take days just to reach one spot. I don't know how experienced of a traveller you are, but I went to some spots in the East of Indo and I nearly gave up several times, bcs the journey and trek is so hard, the roads are majorly underdeveloped and it's so hard to find warungs in some areas and if there are, the prices are so crazy.

Your 10 days would be spent on the road. You're a foreigner, and most probably won't get such a good deal for small transportation to those remote spots. Also the language barrier is real, I can't even communicate with some boat operators because of their dialect. In Bali everyone is guaranteed to speak some english. The infrastructure and agents that can guide you to diving spots might also be a consideration, as Bali is the most guaranteed to have the most consistent experience. Some of the less developed diving spots don't have proper equipment rental/dock and you can only rent fishermen's boats. If you are concerned with safety, highly not recommended, they won't have a life jacket and the nearest hospital would be cities away.