Any suggestions would be much appreciated!

Not clear on what shelving you want to style, you're showing 3 different ones in different woods. Please clarify...

Also, will the shelves remain the same colour as on the pictures (ex. 2 different wood stains)?

Need suggestions for all 3 areas of the kitchen. Yes there are 2 diff wood stains. Not my taste but need to work with it for now

To clarify further, one area is above pantry doors, another is above counter and another is on either side of the wet bar which is behind the cabinet doors

Are these all pictures of your current shelves? I’m confused, also. There are 2 different wood tones…. For an update, I think I would remove the scallops. And in the first picture, maybe also the shelf. Then just use that space in the first picture for two large square, dark baskets for hidden storage of “whatever” - things you don’t use regularly, since they are up high. Since you have a top, things don’t get that dusty. I have an “open cabinet” (vs an open shelf - no top) above our refrigerator with square baskets, where I store things like my “used once a year” silver gravy boat wrapped in Saran Wrap!

I don't know what you own to place on all those shelves so I'm sending examples on how you can styles your shelves Going all white is a good idea. And, as suggested by @chloe00s, baskets with the shelf removed above the pantry doors.

First pic - Two square baskets

Second pic - One white object in the middle of each shelf - a bowl, tea pot, whatever

Third pic - Is this still in the kitchen? What is behind those double doors. Can any of those shelves be removed? I'd take as many out as possible so you have two or three large spaces with one object in each space instead of tons on little decor. Do you need a bar space, anywhere to store bottle of alcohol?

Styling means different things to different folks. You’re focusing on what to put on those shelves The only thing that really matters is the stains.

You may be stuck with two different stains, but you don’t have to live with two stains on the same piece of cabinetry. These should be stained. It involves a bit of effort, but the payoff will be great. If the wood is maple you can either dye them or paint them, but I suspect these are oak and will take stain just fine.

I don’t know why you feel you need to live with it as is, but you really don’t. Good luck whatever you decide to do.

I agree that the scallop-y trims are the most dated features. Couldn’t they easily be popped off from behind? Then fill the nail holes.

Could you find squared-off seagrass baskets to fit in a color very similar to the cabinets? Then maybe the cabinet color wouldn’t look quite so random.

First pick SCREAMS for wine bottle storage!

Second looks like a good place for cook books.

Third is deep...maybe one nice piece each. My MIL had a collection of soup tureens in different shapes, goose, turkey, head of lettuce. Solid white.

Since the third photo shows shelves next to a wet bar (behind the doors per OP's comment), I was thinking that wine bottle storage should go there. OP there are several options if you search for wine bottle holder inserts.

Above the pantry in the first picture seems a good spot of cookbooks, but only if it's easy for you to reach up there.

I was also thinking that the scalloped valances might be easy enough to remove, and I think that would help.

Something else to store (and hide) in big square baskets on the open shelf above the pantry are plastic leftover dishes/ containers. If yours are like mine, they are all different sizes that don’t stack well. They are light enough that you can easily get the basket up and down.