That bit in Romans isn't hell, it's just the traditional Sheol of Judaism
You really have to scratch around in Paul's writings to find he held anything like that concept, and he never names it
I see the Nazarene faction as being the original form of Christianity and that Christianity subsequently became more "Gentilized," and to judge from what Jerome says about them I would say that, depsite tensions regarding Torah observance (as per the Letter of James and Acts 21:18-24), they were "okay with Pau
OK, that theory IS very logical and it can be supported I admit
But there's interesting alternatives
If you bring the Odes of Solomon forward, here you have a rare Jewish-Christian writing that has many pointers to an early date
It is the writing of a messianic Jewish sect, it appears to oppose temple sacrifice and observance of Sabbath and circumcision, a 'spiritual Torah'
Yet it isn't given proper scrutiny it deserves from what it says about itself
It also has many, many similarities with Paul's theology such as salvation by grace, the spiritual body of the messiah, and much more
It also differs from Paul in other respects, such as a lack of emphasis on atonement or sin but the same end result
It also has no hell concept at all, in fact it says the messiah abolished Sheol!
What if this were the original Christianity?
Then you can see how Paul could have emerged from it...
This would make the Nazarene faction a deviant version, perhaps originating from the outskirts of the core Jewish Christian group rather than from it's centre. It has to be considered whether the Nazarene faction was Jewish or Samaritan as well.. the Clementines has many 'Samaratisms'
So here are 3 separate branches of the early church at least, the original 'odes' community, the Pauline and the Nazarene
I think the dispute between Paul and the Nazarenes was very significant in it's day but healed in the decades after leading to the merger
The book of James in the NT can be read as a veiled attack on Paul even
This would make both Paul and the Nazarene's divergences from the original Christianity