a. For this case, if you are an absolute beginner nothing will beat a Honda Rebel 250. This was my first bike and it's literally two bolts and a nut. There is nothing to it, that's how simple it is mechanically. Its main downside is that its underpowered. But it'a also super light which means it is very easy to maneuver as a beginner. I was an absolute beginner when I started out so for me this was a good choice. If you want something a bit more sporty-looking, get a Kawasaki Ninja 250/300/400 or a Honda CBR300 or a Yamaha R3. Again, simple bikes, not much to them easy wrenching. These will be faster (a Ninja 400 can get you into trouble fast). If you want a standard bike (feet under butt vs in front for cruiser or behind for sport bikes), a TU-250 from Suzuki is a low maintenance choice. If you want a cruiser with a bit more oomf, get a Honda Shadow 750. It'll be heavier but still very manageable unless you are relatively small in stature. They are cheap, plentiful, and being a Honda, very easy to work on.
b. If you want more reliable (this is a good way to go because as a new rider the advice is that you should spend more time riding than wrenching), I would get a Kawasaki Vulcan S with ABS for a cruiser, or a Suzuki SV650 for a standard/sport bike. Avoid any bike that has an inline 4 with a total displacement of 600cc. Those bike are proper sport bikes that are not beginner friendly. For example a CBR600 from Honda is going to be stupidly fast compared to a Honda Shadow 750. You can also look at the Honda Rebel 500 ABS. ABS is the key here: bikes without it are more common but the technology really should be on most bikes these days. It makes a big difference when you need to stop fast.
If you reply or message me privately with your specific thoughts I might be able to recommend a more specific set of bikes.
2. MC Garage on YouTube (https://www.amazon.com/Proficient-Motorcycling-Ultimate-Guid...). Make sure to get all the gear, head to toe, and always wear it. Motorcycle accidents can get gnarly, and the gear makes a big difference.
Hope that helps!
P.S.: One of the most entertaining and informative motorcycle info channels on YouTube is https://www.youtube.com/channel/UCNSMdQtn1SuFzCZjfK2C7dQ. I don't think you need to even own a bike to enjoy it.
Just be aware- what is taught in the basic rider course is the most basic elementary stuff. It's also not really everything you need to know- it's just enough to give you a fighting chance of not being killed immediately, and hopefully gives you a solid starting point to improve your skills.
It takes conscious effort to learn riding techniques, and it takes continuous practice to improve. Simply putting on miles without understanding that you need to put focused effort into improving will get you miles under your belt without developing superior skills. Staying alive on the street is a combination of riding skill and observation & planning skills. Some of this you can learn from books, I recommend David L. Hough's books "Proficient Motorcycling" and "Mastering the Ride: More Proficient Motorcycling", and also his "Street Strategies: A Survival Guide for Motorcyclists" book.
And there are many others who have written good books on riding, but those are the ones I own. When my wife and later our kids decided to ride, those are the books I strongly recommended to them.
Take more formal instruction after you have a little experience on the street. The MSF advanced rider course, or a dirt bike school, a police motor office course, anything with a pro instructor. Track days can be good too, if there is good instruction and coaching available. Right now, you don't really know what you don't know.