OP. You can’t just say your going to go for bike x with a 100mm stem and x travel hoping its going to be safe. Mountain-biking is an extreme sport wether you like it or not. If you’re over-reaching for the bars you ain’t gonna be safe. Take a 29er with long stem down a rock garden wthout the proper skills and you’re gonna hurt yerself. Take 6 – 8 inches of travel to a bmx track and you’ll have too much bike.
If there was the right bike then we would all have one…we don’t! What we do strive to get, or have, s the right bike for me.
I don’t know what riding experience you have but I’d seriously suggest getting yourself a cheapish second-hand hardtail ( fat-bike would be ok but more expensive ) and learn to read the terrain and pick your lines. Buying ssafety equipment is a must. Knee & shin protection, helmet with peak, decent shoes & gloves at the very least. And sign up for a skill-course.