Blog Post
Well sometime in the last 2 weeks 2D app multitasking was rolled into my v50 on Quest 2. So you don't have to wait for v51 with luck.
Nice feature. When you start seeing four apps recently used apps, both 2D and 3D, on your Universal Menu you'll know 2D app multitasking is available.
Now if Meta would reinstate app pinning on the Universal Menu we'd really be going somewhere.