Oh Mandy is quite trippy but it's not really obscure anymore it blew up a while ago some obscure ones I love are The Void (eldritch survival horror) and Angst (an Austrian movie based on a manifesto)

I've not seen the Void, but looking at it I feel like you'd enjoy some/all of Analog horror. Something like Midwest Angelica (it's all on YouTube). There seems to be quite a lot of cosmic horror themes in AH. see also Local58 and Gemini Home Entertainment.