My journey out of the SDA church did not really deal with those issues. I always found EGW boring and didn't understand why we would read her if we had the Bible. I grew up being taught that if EGW disagrees with the Bible to toss out EGW so I never really paid much attention to what she had to say. As I was leaving the SDA church I saw the ellenwhite.org site, but it didn't impact me greatly because EGW wasn't high in my book anyway. Also, I never realized that SDAs believed in an incomplete atonement at the cross until after I left the SDA church. Maybe I'm not a good example

I was baptized at a young age after much begging. I was baptized into Christ. My young mind did not understand the complexities of the investigative judgment, but I did know I loved Jesus. That said I did reek of legalism for several years until I had a teacher in academy who taught me that we could have assurance of salvation.
I did sit down and try to prove the 2300 days from the history books. I wanted to see if all those dates were significant. I couldn't find one of them. I'm sure they are in history, but they were not these significant events that I had thought they were. When my views on the remnant status and the Sabbath toppled the SDA prophecy ideas went with them.
The issue that led to me leaving was the remnant status and the mission of the SDA church to convert Christians to SDAism. To get to that point was the work of the Holy Spirit. I had met and was baptized in the Holy Spirit and within a year I left the church completely. He walked me through leaving in baby-steps and gave me a nudge when I needed it. He opened my eyes and I saw things in the Word of God that I had never seen before. I left the church due to the remnant status, but I still called myself SDA until my views changed about the Sabbath. Those views changed about 3 months after leaving. My views on the state of the dead gradually changed over a couple years.
My questionning of SDA doctrine began with something rather silly. I was a student missionary in another country and it was perfectly okay for people there to wear jewelry and it was not okay to wear make-up. It was the opposite in the US. That started me questioning many things.
On and off for many years I would question different issues like the Sabbath and the SDA's view on prophecy. I dealt with these issues on my own and after not finding answers to questions I would usually go back into cognitive dissonance. That process took about 7 years. One girl was very influential. I met a Christian woman who was on fire for God. She had something real and she was not SDA. Her witness was real. Mine was pitiful. I had thought I was witnessing when I told someone I went to church on Saturday.
The baptism of the Holy Spirit
Realizing that my vision and the SDA vision did not match. My vision was to bring the Gospel to the lost. SDAs vision was to bring the 3 angels messages to Christians.
8 years!
No regrets whatsoever although I do miss potlucks

It was the Holy Spirit who led me. At times I questioned what He was doing, but He knew what He was doing. I went to a Bible school shortly after I left the SDA church. It was quite humbling to go from knowing everything to knowing nothing. There will never be an end to learning.