Found the issue!

It was because drawing the texture onto the screen draws on top of the gui. I had to separate the functions out into a "DrawScreenTexture()" function and then just a "SwapWindow()" function. Code now looks like this.

ImGui_ImplOpenGL3_NewFrame();
ImGui_ImplSDL2_NewFrame();
ImGui::NewFrame();

ImGui::Begin("Material Controls");
ImGui::Text("Hello World!");
ImGui::End();

_myFramework.DrawScreenTexture();

ImGui::Render();
ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

_myFramework.SwapWindow();

Also shout out to whoever downvoted my question and to whoever edited my question to take any kind of personality out much appreciated.