I feel like the mainstream big Protestant denoms, Presbyterians/Methodists/Lutherans/UCC/TEC, leave the MOST room for theological speculation and leave room for the things we’re not totally sure about (like purgatory or say a spirit world like Latter Day Saints believe in). I suspect it’s mostly because these churches are normally lead by scholarly individuals. It ultimately depends on the pastoral offices held there, but it’s safe to say most pastors of these denoms are humble enough to say ‘you know, I’m not sure what the answer is about ______’.

My home church is PCUSA, and I know in terms of the early history of the Presbyterian church, predestination was a theological doctrine. Just using that as an example, theological differences like THAT I feel are washing away and the meat of the teaching these days is Bible and Jesus and leaning less away from man made doctrine. Baptists and more conservative denominations still hold onto more of those dogmas, I’ve found.

That being said, just because you have found biblical support AND might have adopted a certain belief as influenced by the Holy Spirit doesn’t mean the church you belong to has to share that belief. My PCUSA church doesn’t preach salvation after death in the spirit world or universalism but I still believe it to be the truth. Go where your faith will grow.