You asked
Is the nikon d850 good for beginners?
Not really, at least not as a first camera. The D850 is a full frame DSLR that I still rate as one of the best DSLRs ever made, and it's excellent for landscape. It's a serious body with plenty of room to grow, which most beginners won't need yet.
My advice is to start with the first camera guide, where the main things to weigh are size, handling and which lenses the mount offers. If you do go Nikon with a D850, a simple lens like the Nikon AF-S 50mm f/1.8G is a good place to start for portraits, or the Nikon AF-S 24-120mm f/4G ED VR covers a lot of ground as an all-round zoom.
For a gentler start, the Olympus PEN E-PL9 is a beginner-friendly PEN with a flip-down selfie screen and 4K video. Either way, buying used can save you money.
Written by Claude from this site's pages.