I know this is for people with a natal stellium in the 12H but hear me out lol: I have my natal mars in 7H conjunct NN. Mars rules my 12H.
I have a 6H stellium.
A guy I dated previously had Venus in the 6H. Venus ruled his 12H.
In synastry, my stellium was jam packed in his 12H.
His Venus in mine.
Our relationship was very low key and intimate in terms of the overall vibe. He was very much emotionally unavailable most of the time unfortunately.
But back to your original question:
In terms of material things, our relationship actually suffered a great deal because of that very thing.
We didn't lack resources and material things per sé.. we just lacked them during our relationship. The 12H feels like a Black hole almost in that once you get sucked in, you won't be coming out. And science aside, even if you do make it out, you won't be the same and you can't really explain what happened while you were in there.
When me and ex first met, he worked A LOT.. was obsessed with clothes, his SRT sports car, and his 3 fake cuban links. Our first two dates were Hornets games.
When me and ex settled into the relationship, the materials slowly started disappearing. We smoked tons of weed and ate out almost every day. It was actually one of the best times of my life, but staying in topic here...
He was still obsessed with materials.. but my financial situation was completely ruined during the time so the circumstances kind of forced the balancing of the scales so to speak..
My ex still worked and actually started making more money than he ever did in his life, but me being the total opposite of materialistic AND being in a tough bind, the focus shifted away from the outside world for basically the remainder of our relationship.
Material things will not survive in a 12H chart. Or if they do, it will be like background noise compared to the more pressing issues associated with the 12h like healing (or self-undoing) and fantasies.
Anxiety is another biggie not really talked about in terms of the 12h that should definitely be examined more closely.
I had major anxiety all throughout the relationship even though my answer is extremely biased because i was also going through a moon square Pluto transit during the time.
But Astrology overlaps and one thing inevitably explains another if you're looking hard enough lol.
Anyway, I used to have panic attacks mainly in the mornings right after my ex would leave for work. This was right after I graduated college and had some major domestic issues with my parents which actually led me to living with him for the most part. We talked about it all the time but never really seriously considered it until my Narcissistic father started kicking me out every day and purposely sabotaged any decent job opportunities that came way (The 12H gets deeeeeeeeep). Prior to this, I was a workaholic almost with a full life and a busy schedule. Fast-forward, I was an antisocial burnout pot smoker who never combs her hair.
The 12h is definitely associated with mental illness, healing, and simply looking within for answers.. and you can't really do that focusing on the material world.