With this budget there are a number of good options, but others are most likely in a better place to comment than me. I had more expensive optics, but then swapped out for a cabelas covenant - yeah, sounds nuts but works for what I want.
A well designed quick detach is a very good idea, just make sure you mount in the same place as XCR rails are not T marked. This will be very handy when swapping optics for close / far and barrel swaps. I've been looking very closely at Kinetic Development Group mounts, and I recommend you have a close look at those, well priced in the market and have proven return to zero mounting.