Since OpenGL 4.3 comes via the driver, you need the latest driver for your specific GPU.
Modern drivers (2020–2023) support up to OpenGL 4.6. If you install the latest driver for your GPU, you automatically get OpenGL 4.3+ support. You do not need a "legacy" 4.3 download. Opengl 4.3 Download Windows 10 64 Bit
: Programs like Blender 4.0+ specifically require OpenGL 4.3 or higher to function. Since OpenGL 4