If you want to go cheap but still have a decent camera, get a DJI Phantom 4 series. Very affordable used and can carry the 500g you require. Plus there are many load release attachments available online. I'm still flying a few P4Ps because of...
I have a Mavic 2 pro that I no longer use. The batteries were all down to 90% life and all cycled down to zero and full recharged to maintain balanced cells frequently. I’d say well maintained. But in very cold weather I saw scary cell deviation...