Best way to redecorate old plaster walls

[Nytefurio]

Hi

Just looking for some advice, I have removed old wallpaper in small box room, there is quite a few cracks in the old plaster some deep some hairline, I wondered what the best way to redecorate these walls would be, I removed all the old plaster in my last room but that was a main bedroom and didn't want to spend as much. Ideally if I could, I wanted to fill and paint but wanted to know if I would be able to do that or would I have to paper over? What preparation would be needed also.

Thanks in advance
Nyte