I built a 2x2 under over door a while ago. I've never seen another one so I decided I would post it. I had the idea to build this a few years ago while watching one of Mumbo Jumbo's videos. Now, after a few years of procrastinating and a few more learning redstone, it's finally built. I know under over doors aren't super popular but I like them and it was a fun build and it's fun to use. Having the doors open is optional, just remove the light blue redstone line to disable it. The ring of immovable blocks is necessary. I might build a version later that doesn't require it.
In case I screwed up setting the spawn point, the build is at x1 y1 z12