Shechina is a concept clearly outlined in the seforim – it is not a physical manifestation of Hashem cv”s or another “part” of Hashem. It is his restricted presence that he makes palpable – it can be compared to covering a bright light with many levels of sheets. When you remove some layers from one area, the light is visible, but it’s really all there underneath. This is how the tanna answered the goyishe philosopher who asked him “how much shechina do you have?”, He did use a different moshol though…a dark building opening up a small window to let in light.
Same thing with the shechina being in a specific place – it’s wherever Hashem opens up the window kiviyachol
That has no bearing on a claim that gods essence has become wrapped in a body. Also, atzmus elokus is not a term for the shechina – if you have a source that says otherwise, please let me know as i am not an expert in chasidus.