I'll try to keep this short, I have a tendency to ramble.

I want to make a container where the player does the idle 'greybeardmeditate' when they use it. I can't find anything on any websites on how to do this.

I'm a relative noob, fyi.

In further detail, the container will either look like a rug, or something on the wall, and will (respectively) kneel on it or 'meditate' towards it.

The 'greybeardmeditate' is a furniture. I think you cannot use it as a container.

You may look at my house mod Sepredia where I added such a meditate furniture marker for the player (and some other too).

I was thinking that I could possibly do it like the enchanting table or workbench and have it open a chest menu or something like that.

I think you can add a chest as visible object but you will not be able to use it as a container at the same time. Either idle furniture - or container.

Oh well. Thanks.