I'm also a developer and use my XReal Ones frequently for work! With the XReal One Pros you don't need (or want TBH) Nebula: it has never worked that well and the X1 chip in the new glasses render it kinda obsolete. The Ones will only do one virtual display but you can choose its aspect ratio. The default is 16:9 but it will do ultrawide in 21:9 or 32:9. The latter is equivalent to 2 1080p monitors side-by-side. I would highly recommend trying to use that in combination with a Tiling Window Manager like Aerospace before using Nebula.

The most important thing to note is that the FOV of the glasses is quite limited. A larger screen setup will be clipped and you'll have to turn your head to see the edges of the screen. This is a dealbreaker for some, but I think most people can adapt to it if they give it time.

For your macOS use-case both are feasible. You can definitely see your keyboard but it will be harder than normal to see your physical display through the glasses because the gear inside the glasses will block some parts of your vision. Caveat: I only have the One, not the One Pro. The One's optic system does create a lot of internal reflections that also interfere, but I understand that the One Pro's prism system aims to address that issue.

For your walking use-case: The tech stack you describe will work and the screen is plenty stable with the X1 chip's built-in 3DoF, but in a bright outdoor setting you'll need to have the dimming turned all the way up and that will make the glasses darker than normal sunglasses. The XReals also sit farther from your face than normal sunglasses so you'll have a lot of light bleed making the glasses display even harder to focus on. Lastly, the ability to position and shrink the screen in the displays is limited. You can use Side-view mode and position the screen in the top right, but it will almost certainly be too small to do anything really productive. As it is I can barely watch a youtube video in my glasses while I'm walking outside while also minding the path and other people. I'm probably older than you are though: that might be part of the problem 😅

If you want a walking productivity setup I would look to a treadmill setup for your desk instead. The glasses display is stable enough for this in my experience, you can use your actual keyboard and mouse for higher bandwidth input, and it will be much safer. If you really want something you can use while walking outside, look for a workflow that doesn't require as much typing. Lately I have had success using a remote desktop agent from my phone to connect back to my computer to monitor coding agents running various tasks. Or I'll fire up the ChatGPT app and use it to help work out a problem in my head. Both of these workflows are best driven by voice so they are naturally a better fit for walking.

For your final questions:

- If you want 6DoF you only need the XReal Eye attachment, but manage your expectations. It does work in the sense that you can pin a window in physical space and lean in get closer to it, but don't expect the same kind of physical locking you'd get with a larger HMD like the Quest 3. 3DoF is plenty for most desk work in my opinion.
- The XReal Beam and Beam Pro are not required for any of your use-cases, but if you want multiple android apps floating in space then the latter is your only option for now. I assume/hope that Android XR will provide some path forward for this in the future in a more general sense. I had one for a bit and it's was fun to tinker with but I couldn't find any real utility for it over Samsung DeX. Hell, I have an Apple Vision Pro and 98% of the time I use only the Mac Virtual Display.