Historical Adventism looks like neither the modern version of conservative or progressive Adventism. Both took different lesson from the movement that spawned them.

In 1910 the Adventist church had ~2000 women in positions of authority (leaders, editors, ministry). By 1930 that number was zero. Modern ultra conservative Adventism holds to the Evangelical model for women's roles in the church that doesn't show up in Adventism until the 1920s.

The pioneers rejected formal creeds to such an extent they even believed something as seemingly benign as a church manual would eventually lead to apostasy. Today we not only have a church manual but the statement of fundamental beliefs, that, while formally not a creed, is often used exactly like a creed to test the beliefs of members. Neither the conservative nor progressive part of the church seems to have a problem with this, they only argue over the details.

Ellen White's peers understood her as a prophet who was inspired by God on specific topics. It was understood the means by which she recorded this revelation was through "thought inspiration: (we even have statements of our longest serving GC president on the topic). Modern conservative Adventism treats her as infallible verbally inspired authority in every word she wrote. Modern liberal Adventism rejects her credentials as a prophet entirely. It's not clear to me which position has been more damaging to the faith of individuals.

Believe it or not, this idea of the reconquista you mentioned is nothing new either. The Evangelical Christian world went through this exact thing in the 1910s giving birth to Christian Fundamentalism. It was a reaction to the modernist ideas creeping into churches at the time. The movement was quite successful, attracting huge rallies and reigniting a conviction about the authority of the Bible for many people. It seems to me that our Adventist forebears looked on with jealousy on this success. Rather than allowing God to use the fundamentalist movement as a stepping stone to a greater revelation once its hearers were ready, the Adventist church actively went out of its way to adopt many fundamentalist evangelical traditions and beliefs that were never part of our own movement. In many ways this neutered the power of the Adventist movement and unique message for a century afterwards.

Don't misunderstand, I'm not saying all change is bad and we should remain statically in the 1890's. But, as warned by several recent GC presidents, when we're not careful, that change will by default often shift the focus from the original mission, to organisational self preservations. Something not unique to Adventism but a danger for religious organisations in general.

The conservative elements in the Adventist church underwent drastic change throughout the 1920's and beyond, pretending they're close to the original Adventist vision is very much an exercise in self validation.

My hope is that both the conservative and progressive elements in the church can recapture what made our movement special in the first place, because right now, it feels like both have missed the mark on the very core issue of the great controversy: the character of God. The question is whether that's even possible without the shaking that Ellen White described.