This is a plugin expanding features of OBS, so it's worth to try out.
But it didn't work well for my case. I already use bounding box and alignment options - both for positioning and positioning inside the bounding box, both of which are required to be same for the transition - for aligning sources.
Therefore having to sync all the three properties of each corresponding sources just for one external plugin is really unpleasant, as these properties of the sources are now dependent on it. In fact I was refusing to try this plugin for months since knowing this is required for the plugin to work.
I had to change so much, while the plugin yet can't offer some features I really needed to compensate.
Once I thought about making a transition for moving my layout but it didn't work well, so I end up having my own bezier curve I want to use someday. The available 'Back' transition is too wild for me, so I want to use a custom bezier curve.
I hope I can also exclude some sources even though they're seen matching, and that I can treat them as appearing and disappearing items. I shouldn't duplicate a same group of sources to exclude them from the transition. I saw there's an override filter that can be used for sources or a group, but it can't override the matching state.
A plugin worth to try it, but with some bad aftertastes that couldn't be cleansed with yet.
You can always contact me via the OBS discord server if you are willing to give it an other try with my help.