Welcome to the community!
While I’ve been told that OH is a more stable than HA I do want you to realize going in that to achieve “set it and forget it” requires a lot of work up front and the longer you wait between upgrades the more work it will be on you.
Coincidentally I just wrote a quick tutorial with some advice for how to achieve this at I don't want to upgrade! How to put it off as long as possible but the overall tl;dr is don’t change anything!. So you truly need to set it and forget it, no new devices, rules, UI widgets, OS upgrades, additional software, anything. It also means limited reliance on external services like cloud based APIs. Any change you make after first setting it up might break something and if it’s been a long time since that version of OH was released there will not be many who can help left and if it’s a bug, you’ll have to upgrade to get the fix anyway.
I believe the deCONZ binding is what you will need to use as the Zigbee binding doesn’t support this coordinator I believe. Xiaomi is notorious for adding on to the Zigbee standard so I don’t know whether that binding supports Aqara sensors or not.
I don’t know this camera but if it supports RTSP or ONVIF. That camera is not reported as working but it’s also not reported as not working. IpCamera: New IP Camera Binding
There is a Node Red add-on for openHAB support. Node Red can also be installed with openHABian.
openHAB has an HTTP binding that likely will work for you.
I’ve not migrated from HA so I can’t point out anything there. In general some advice getting started with OH includes:
- Use the docs. Even if you think you know something if you run into trouble look at the docs again.
- Use the forum. Search and if you don’t find anything ask a question. Don’t spin your wheels for hours and hours. But when you do ask on the forum, show your work. If we see you’ve tried and what you’ve tried it makes it easier to help.
- Start small. OH has a lot of concepts that need to be understood individually and how they work together.
- Use the Getting Started Tutorial as a guide. But realize that it presents examples. You’ll need to get good at generalizing an example and applying it in a different context. For example, the Adding Things Advanced page talks about MQTT but the HTTP binding is going to work very similarly.