Hi sifu, planning to paint a new color for my room, wanna see for some advise

Currently my room is in light blue, and would like to paint to white/cream. I tested the paint on my wall and it can't cover the old color.

Question: Should I paint my wall with white paint first or use primer?

If primer, what brand do you guys recommend? Quite surprised that Jotun Majestic primer cost the same as the Majestic paint. I believe there's cheaper primer out there but not sure on the quality and not sure if i should cheap out on primer.

Seeking for advise, thanks in advance!