If you have perfect equipment, for example, a key ring, a pick, a pick bag (if you just finger-play, you can choose to wear it on your finger if necessary), a tuner (it is recommended to buy the one with indicator light, which is cheap and practical), a music stand and a metronome (mechanical metronome is generally used for guitars, but it is more expensive, but I personally don't think it is necessary to buy a metronome.

Creative words: On the basis of playing the guitar well, buy a book on music theory to learn music theory knowledge (I recommend Li Zhongguang's book Basic Music Theory), a notebook computer (with some music production software, such as Nuendo, Cubase, Sonar, Flstudio), and a MIDI keyboard (this is easy to learn, but if you are proficient in the previous three or four softwares, you should be able to do without MIDI).

I hope I can help you!