The difference between SLR and ordinary cameras is that SLR lenses can be replaced. (Of course, changing lenses costs money)
You can buy lenses with different focal lengths according to the different subjects you shoot.
SLR also has manual function. (Of course, there are also many people who use SLRs as point-and-shoot cameras)
So if you want to learn photography, it is better to consider a SLR camera.
For new models, you can consider entry-level models such as Canon 550D or Nikon’s D3100. Relatively cost-effective.
If the budget is tight, consider a second-hand machine.
Canon is the 30D and Nikon is the D70s. Relatively cost-effective and practical.
It is recommended not to consider other brands. The reason is that Canon and Nikon have more lenses, and there are more sub-factory lenses to choose from.
As far as teaching materials are concerned, it is enough to have an introductory textbook.
There is no best teaching material, only how well you learn. The introductory textbooks are basically the same. They just describe some of the working principles of cameras and basic picture shooting techniques. Once you gradually understand what you want to shoot, you can then learn and practice shooting accordingly.
Photography is art and photography is entertainment. If you want to take pictures, then go and improve your artistic accomplishment and aesthetics. (Especially art) After all, you first need to know what kind of photos are beautiful and what kind of photos are artistic.
Photography is a long process, (it is also a process of spending money), don’t be impatient, as long as you take enough photos, you will slowly learn some tricks. Of course, you don’t need to press the shutter button blindly. You should consider what to shoot before pressing it. Why shoot? How to shoot? Wait for 3 questions.
Then I wish you early success. The above is my humble opinion and is for reference only.