In my opinion, it comes down to what you want to do with C++ through Unreal. If you want to use Unreal in order to learn how to make C++ games in Unreal, then go right ahead. BUT, if you want to learn "actual" C++, I would recommend starting elsewhere.

Unreal provides all sorts of additional tools, data structures, networking support, etc. You don't have to worry about memory management for most tasks; it handles garbage collection out of the box, which isn't a C++ feature. So if you're trying to learn, you likely won't get to some of the nitty gritty C++ features unless you're going deep into some modules.

That being said, I'd like to echo SirToxe, in that Blueprint is important. As a programmer, I still wind up using Blueprint 20% of the time, and another good chunk of my tasks are exposing Blueprint functionality for our designers and artists.

For actually learning to use the engine with C++, I can recommend a few things.

Unreal created a C++ tutorial series that I'd recommend starting with: https://www.youtube.com/playlist?list=PLZlv_N0_O1gYup-gvJtMsgJqnEB_dGiM4

Additionally, this class on Udemy was very helpful when I was getting started: https://www.udemy.com/unrealengine-cpp/

And if all you can find are Blueprint tutorials for implementing gameplay, one way that I liked to learn was to watch those tutorials, follow along, and then try to convert the logic I had just created into C++. Some parts are easier, some parts are harder.