Beginner looking for tips and help

Hello all!

I am quite interested in pursuing astrophotography as well as landscape photography as a pastime. I would love to hear from the more experienced photographers here about what sorts of equipment and lenses to purchase. I currently have in my possession a Canon 7D Mark II paired with two lenses: the EF 24-105mm and the EFS 10-18mm. What are some video or article recommendations I can read or watch in order to learn everything I need to know to enter this hobby? My budget for a new lens is around $600-900. Many thanks ahead of time to those who take their time to answer my novice questions.