It is simple
it’s a new texture and a new project
That’s a lot of code. Maybe that’s your problem. You either don’t understand it or the API
You can see how little is required in this thread. idle not at 0% and here’s another one that uses SDL_CreateTextureFromSurface and SDL_RenderCopy to put the texture on screen. But that code is SDL2 SDL_RenderGeometry slower than SDL_RenderCopy?
I refer to this page so often that I use bookmarked the my offline version (online site doesn’t like you opening many pages at once) SDL3/APIByCategory - SDL Wiki