Enterprises are not schools. If you misunderstand, you will never find a suitable job. As for those companies that get started quickly, it depends on personal ability. Enterprises are places to work, not experimental bases. Only if you have that ability, you will do it naturally, and the boss is afraid that you won't do it. In addition, don't rush to achieve anything you learn. What you learn in half a year may be learned by others in a month. Only by starting from the basics (maybe those jobs are marginal jobs in your eyes), the talents accumulated by time and practice are the people that enterprises want to hire most. As for Siemens PLC, I can tell you that most enterprises are using it, and Siemens Mitsubishi AB is the mainstream. I believe that any enterprise will also let you contact him and learn from him.