Carris, as I said above, the OPer doesn't own or control a thread. On most threads of any length or interest, you will find people posting about their own particular interest in the broader issues raised by the thread's general theme. I guess the old-timers here are used to it. My best advice for anyone who doesn't like my posts, is just ignore them.
Regarding Hellenistic astrology (indeed, the European Dark Ages were the heyday of Arab astrology): if the 12th house really has a spiritual component, as you suggest in your OP, it may be that some 12th-house people turn to contemplation and acceptance of What-Is through fully experiencing and accepting life's difficulties. Most mystical teachings indicate that one has to let go of one's ego and its jockeying for position, if we are to manifest spirituality in our lives.
I have one planet in the 12th house. I would say it fits one reading of the 12th house, that the operating mode of planets here may be inivisble to the native, although everyone else can see their operation fully!
My daughter has her sun-Mercury in the 12th, with a strong 12th-6th house axis. I think she experiences the 12th as the traditional "house of self-undoing." She is not a self-promoter, yet she tends to resent people who get more in their lives with less talent than she's got, and less effort than she expends. She has the capacity to be extremely selfless, and is now doing very well in a post-graduate program for a service type of career.
I've spent some time looking at charts of notable mystics and religious people to see whether they have strong 12th houses, Some do, some don't. So here's just a little modern history, and then a recap.
The 12th had a rotten reputation until modern astrology emerged from traditional astrology's ashes, in the late 19th century. Like you, these "new" astrologers were totally turned off by the doom-and-gloom mentality of a lot of traditional astrology. They were also seriously into mysticism. So then the 12th got a hugely boosted reputation that it possibly didn't deserve. As the "last" house it had to be the pinnacle of human evolution. Because some well-known religious folks had strong 12th houses, this had to be the house par excellence of spirituality. This kind of demoted the 9th house to focusing merely on long-distance travel. I don't know if it's still there, but there was a New Age book store in Denver called The Twelfth House. Twelfth house was good.
Starting about 20 years ago, there was a big resurgence of interest in traditional astrology. You see this with some of our members. To them, the "Dark Ages" weren't "in the dark" but were a rigorous alternative to what they see as Astrology Lite in today's woo-woo modern astrology. They would argue that sometimes life does reek. Bad things do happen to good people. We shouldn't try to paper over harsh realities, and the 12th house is one that can indicate something about how they appear for us. Yet even in traditional astrology, there can be mitigating circumstances for 12th house placements.
To recap:
1. Bad things do happen to good people. Somethings we need to let go and accept life as it comes. Ideally, by letting go of our egos (sun in the 12th) we can open up to deeper realities.
2. Some people are hospitalized, imprisioned, institutionalized, or shut-in in some way. The 12th house rules them. Twelfth housers don't have to be like this, but they might benefit from working with such people.
3. "Your best friends won't tell you, but ..... " Sometimes parts of ourselves are hidden territory to us, yet they are highly visible to others. Any 12th house planets can indicate what these are.
In this "house of self undoing" perhaps Mars doesn't function with normal assertiveness and the person copes with low self-esteem. She doesn't quite understand that she doesn't need to see herself as inferior to other people, even though they wish she would come out of her shell more often. Someone with Saturn in the 12th might not see himself as bossy or super-critical, but this is how he might appear to others.
4. Did Mom have a difficult labour and delivery? An overwhelming sense of responsibility or inadequacy after you were born? An afflicted 12th house planet might indicate this.
5. Was Dad either physically absent from the child's life, or emotionally distant and seldom home? Saturn in the 12th can indicate this.
6. Can you identify with a cause or group of people bigger than yourself? This is an excellent use of a 12th house sun. You see this with 12 house sun politicians. If someone has a strong 12 house axis, they are said to have a "serve or suffer" lifetime. For example, a teacher might strongly identify (sun) with the good of her students, her school, or subject area.
7. 12th house people (as well as 8th and 4th house people) tend to enjoy working behind-the-scenes. It's as though planets here don't enjoy being in the spotlight. If other chart indicators suggest that the person is a raging extrovert with more Lion or Ram than the Brooklyn zoo, dedicating themselves to a higher cause (which they can lead) is usually a way to satisfy both the 12th house and the more publicity-seeking parts of their chart.