Teaching niche is really interesting and profitable in countries like India where there are millions of students ready to consume your content for free. There are many successful coaching channels out there in India too.
Important thing to note here is that students relate to the personality of the teacher and they will follow only those whose personality has a charm, teaching style is appealing and impressive. Since your channel is going to be faceless, I am not sure how you are going to connect with your audience.
Also, I am not sure how will it work in another country like French or Arabic speaking country. You will have to start teaching it first and then analyze the result yourself.
Any software will do, like Filmora or Movavi. Just stay away from the free versions of software's that leave the watermark on your videos. That just don't look professional.