This is fine if you do not plan to share your work with others, but it's not well-written C++. It will bite you later on. It's best to learn the C++ way of doing things. It will save you so much time and headache. Don't use character arrays, use strings. Don't use C arrays, use std::vector or std::array. Don't write your own lists or sets, use std::list/set or std::unordered_list/set. Don't use strcat when std::string operator + exists. Etc.

I personally rarely use smart pointers or make_shared/make_unique these days. I just don't need pointers. Most of the time allocation can be done without them, and when I need to pass things around I use references. There are exceptions for C APIs for cross-platform/cross-compiler work, of course. And sometimes library code needs it, ofc.

The STL and <algorithm> are your friend. They solve so many problems in a very elegant way. Learning them should be a priority.

I'd go easy on the OOP elements unless you know OOP programming very well. Just using classes as containers for data and functions is more than fine for C++ most of the time.

Writing your own templates can be a bit of a footgun until you understand them. Feel free to put that off awhile.

Don't mess with volatile and asm unless you are 100% sure that what you're doing needs it.

Also: Be cautious with use of auto. A bit here and there is fine, but too much and code can become unreadable. C++ is a typed language for a reason.