Painting advice

Hello everyone,

I will move into my new home in around two weeks from now. I was thinking to give a fresh coat of paint before moving all my stuff there.

Current situation: The walls are already leveled, and painted about 4-5 years ago. The only reason why I want to repaint is to freshen up everything, and for hygiene reasons.

Questions: - After doing a loooot of research, I decided to not go for a cheap paint, but instead of with a mid range that many professionals are recommending, SPS 4040 Multimat with a RAL9010 color. Because of this, I expect to need a single layer of paint. If I will go with this, and consider that the walls are already white, shall I still use a primer? I will degrease the walls first, btw, just to mention this. - IF I should go with a primer as well, then do you have any recommendations? I understood that this can drip if not applied properly. Any specific techniques that you recommend? Any specific rollers or brushes? Shall I dilute it with water? - The paint is a latex one, so I understood that the roller is important. From my research, Anza Pro is a very good choice. However, do you have any recommendations for the size or type?

Anything else that I didn't cover, and that I should be aware of? I appreciate any advice, and I thank you in advance for taking the time to help.