I am considering a career as an Islamic researcher/lecturer /teacher.
can you please give me some advice .

My advise will be as follows
1. Seek the pleasure of Allah in all that you do
2. Enroll online Studies with institutions such as Islamic university college of london (ICAS). This will be give you some good background
3. Reading Islamic books to enhance your understanding from time to time will also help a lot
Feel free to contact me at any time insha Allah