If you are experienced with python, doing backend with Django/Flask seems reasonable.
I was working with both in past, from my experience I would suggest reading a little bit about Flask and Django and decide which of them is better for your needs. Just google "Flask and Django differences".
In short, Flask is elastic but most of the things you have to code on your own.
On the other hand, Django gives you a lot of ready-to-use stuff like migrations, orm, admin panel, a bunch of mixins, permissions, etc. but it is not always so elastic as doing something on your own with Flask.
There are other web frameworks but these two are probably the most popular.
and btw, the main question:
Yes, python is worth learning, IMO.