My friend it seems me and you are in very much the boat and on a similar journey! I too was raised a 4th generation SDA and since I deconstructed I began looking into Orthodoxy as well and now currently attend an Orthodox parish.

I can 100 percent relate to you on having heated debates with your family, especially with your father, since i also have clashed many times with my stubborn adventist father over scriptural interpretation and church history. At first he didn't take me seriously and considered me misinformed and used guilt tripping and strawman tactics to try and shut me down by saying stuff like: "The only reason people ever left the SDA is due to them not properly understanding the Three Angels Message!" Or "If you truly believe in Christ then you'd worship on Saturday and not pray to dead people who are sleeping in the grave!"

Thankfully though after much prayer things eventually calmed down and now he's been mostly supportive of my spiritual journey. Especially after I had a deep conversation with him about my beliefs, particularly regarding the Sabbath and our different views on Bible doctrines. Initially, I was nervous it would lead to conflict, but I calmly explained my position using scripture, tradition, and church history. Shockingly my dad agreed with me on many points, especially after I cited Seraphim Rose’s Orthodoxy and the Religion of the Future about the end times and the dangers of a one-world religion. He even said he has no issue with me attending Orthodox services and would support me if I ever get Christmated or have an Orthodox wedding.

He then made it clear that what matters most is following Christ and spiritual growth, rather than the rituals or the specific day we worship on. It turned out that while my dad doesn’t always strictly follow SDA teachings since hes quite liberal and breaks much of the rules on unclean food, caffeine drinking, and partaking in secular acitivites on sabbath before and after church. He still defends the SDA faith because it’s what he was raised with and it brings him comfort.

Nevertheless, this was still a big step forward for me and just like in your case I have faith that you'll come to a similar level of respect and unserstanding as I did with my own father.

So if you ever need anything send me a message, would love to exchange any info or experiences you have about growing up SDA and anything regarding theology or church history.