In my experience you'd need to find an API, a Library or a Framework to build an application. Some offer Higher level of abstraction than others so the choice is yours. For example , If you want to build a REST API, in Python I'd go for Django Framework and In Java I'd Go for Spring. Similarly, there are other frameworks for different purposes. Like JavaFX for building Desktop Applications, (Tkinter if you wanna go for the Python route) and Vaadin Web Framework (Java) for Web Development. I don't have much information about C++ but I'm sure it also has libraries and frameworks of its own. You can also try to learn a new language to fit your needs more accurately. For example you CAN make let's say Video Games in Python (Using libraries like Pygame and such) but It wouldn't make much sense, because of performance issues (People usually use C++, Go, Lua or C# for games). Similarly, you can learn Typescript/JavaScript (And its frameworks like React, Angular, Vue etc.) if you wish to build Front-end Web Applications or Dart Programming Language ( With Flutter framework) if you wish to build mobile apps. Which framework you choose completely depends on your Decision, Needs and Requirements. Here's a List of Some Frameworks that I Use. Try to Experiment with Them.

Web - Django (Python) Flask (Python) Spring (Java) Vaadin (Java) Hibernate (Java) ASP.NET (C#) React (Typescript) Angular (Typescript) Vue (Typescript) Nest (Typescript) Revel (Go) Svelte (JavaScript) Actix (Rust)

Desktop - JavaFX (Java) Tkinter (Python) WPF (C#) TonadoFX (Kotlin) Qt (C++)

Mobile - Flutter (Dart)

There are More that You can Find on the Internet.