No expert here, but I prefer the solid blue. It’s a softer, more subtle look and I think more versatile.

Whatever headboard you select it's important that it be tall enough to accommodate the size of the pillows you plan to use on the bed.

It really depends on what the rest of your bedroom looks like. Will either choice go with the wall color, the flooring/rug, the other furnishings?

Light blue solid, depending the other elements in the space: )

Unless you are the type who never falls out of love with decor? I'd never advise a patterned headboard.

What else is in the room, side tables ,carpet or area rug, etc......

Pictures.......and plan will get you more advice

I have no clue there is no context . The whole space and what is planned for the space all has an effect on this choice too. For sure no pattern but the could maybe work who knows. Post pics of the actual space and the actual bedding

Since you are starting from scratch (?) you’re in the position to decide how you want the room to feel overall/its style and then able to decide how to achieve - do you have anything chosen/bought? It’s hard to comment without knowing what you are already working with.

Palm headboard: are you comfortable with mixing patterns and being locked into working around it, as it will always dictate choices.

Solid headboard: you’ll have a wider range of decor and color options + an easier time to coordinate.

I would prefer a solid headboard, and do have one, so then I could change out other things to add design etc

FYI I find blues very difficult to work with so tend to use in smaller prints