What gear you need depends upon the field of photography you want to follow. Photography is an extremely wide subject. For many fields you need or it helps to have specialized gear, and you need knowledge and a strategy thats adapted to the field. A sports photographer for example will take a bazillion of pictures to get that one frame that nails it. A landscape photographer on the other hand typically doesnt take many pictures, even might only take one picture in a day and have "nailed" it. Ansel Adams, the most famous landscape photographer, said a good picture per month is a good year. You can also see a skilled landscape photographer in action on YouTube on
Thomas Heaton's channel. Especially also the many failures to get a picture and the many cases when a picture was only there for a split second.
Gear you need also varies wildly, for example:
For a landscape photographer: a tripod is a definite musthave, polarizer is an absolute musthave, gradient ND filter is basically a musthave as well, 3 stop and 10 stop ND filters are also musthaves for many possible subjects, and a cable release should be considered as well. And you dont need bright lenses, but you need to cover a wide range of focal lengths, especially wide angle. A wide angle prime of 20mm to 24mm (small format/full frame equivalent) or a wide angle zoom is suggested. You also need good post processing and be able to do HDR, focus stacking, and panorama series.
For a portrait photographer: a HSS capable camera, preferably full frame , flash, light reflectors of various types (white / gold), and at least one bright portrait prime lens in the range of most typically 85 to 135mm, or at least one of the rare bright zooms with good Bokeh, like the AF 80-200mm f2.8. You want at least a flash cable - news reporter keep their flash on their camera, for everybody else flash on the camera is horrible light.
Studio photographer: Obviously you can collect all kinds of gear quickly for that. I would say at least 3 flash units is pretty much mandatory for studio, as well as remote control to change their power settings on the camera without having to run around.
Wildlife photographer: capable sports camera with good high ISO, preferably APS-C for the crop factor and extra range, capable telephoto lenses, possibly a 1.4x exdender on top of that.
Macro photographer: macro lens (duh), macro flash, tripod, cable release (you can use the delayed release instead of course), macro rail, post processing capabilities - especially focus stacking. Did I forget anything ? And that didnt get into the possible subject matters yet.
etc