Midjourney is decidedly underwhelming if you've spent any time using the expansive tooling and control nets of Stable Diffusion. Yes, it's easy to get impressive first gens with MJ, but all of the coolest work and integration happening is using SD.
SDXL and controlnet is odd a lot of the time. 1.5 + controlnet still seem to give quicker and better results.
Basically SD atleast seems to be for when you want unique content. MJ/Dalle for everything else.
You cant customize basically anything but they look great.
The Stable Diffusion web interface that got a lot of people's attention originally was Automatic1111: https://github.com/AUTOMATIC1111/stable-diffusion-webui
Fooocus is definitely more beginner friendly. It does a lot of the prompt engineering for you. Automatic1111 has a ton of plugins, most notably ControlNet which gives you fine grained control over the images, but there is a learning curve.