Ok first off the bible is contradictory when it comes to the sabbath. 2 Jesus said nothing about eating blood especially killing yourself by not taking in blood. Math 12 Jesus says we desire mercy not sacrifice and in math 15 nothing eaten can defile a man. Also science shows us that in every drop of human breast milk there is roughly 1 million white blood cells .
As far as them being right about holidays not, read Romans chapter 14 and Colossians . Hell fire is talked about in the New Testament and Jesus did go to the underworld.
Trinity was not a concern be early Christians because they were worshipping Jesus and the new promoted God. The church only made the trinity a deal when others were saying that Jesus was an invented God as well as some other issues so they made Jesus a trinity with his father.
Keep up your research and maybe since the sabbath is a big deal to you, you should look into the 7 th day Adventists ...oh and one other thing 800,000 years of ice core samples drilled out of the South Pole show no world wide flood event. The Grand Canyon again second deepest canyon in the world and millions of years old and it shows no sediment layer of a flood. Again check out the ice cores