At that price point and size I am going to recommend you find one second hand. Puruse your FB Marketplace and local consignment shops. If you don't need drawers in the desk look for smaller scaled dining tables.

As far as what it should look like. What does the rest of your space/home look like? What colors are in your home? Do you want the space to be modern or traditional? Feminine or masculine? Have you searched for inspriation photos to nail down what you like?

You can absolutely get something off Wayfair for less than that.

Ikea sells desks for less than the cost of two filing cabinets and an old door, which is what I used to use back before home computers were available. But that may be beside the point.

What kind of desk will you actually use? Do you have a desktop computer? Do you want a keyboard tray?

Or do you rely on parchment, and write on a sloping surface, and need a stool, and a supply of quill pens, and some iron gall ink?

Do you keep paper files? Do you use hanging file folders, binders, or something else to store them? (How much of that paper can you eliminate by using a scanner and a shredder?)

Think your needs through thoroughly. Go to stores and test-sit. Buy the most ergonomic choice you can afford. And if you really plan to spend a lot of time sitting at a desk, save up and invest in a first-class desk chair that will support your back and allow you to fit your knees comfortably under your desk. That, IMO, would be money truly well spent.

Compared to the ergonomic considerations, color is immaterial.

Consider putting the $500 towards a used desk (found this on Marketplace in 2 minutes). Mixing woods and styles are done all the time.

Spend the balance on acessorizing and a rug would be a great addition to add some color and interest.

Your needs for type of desk are what is important , matching the other piece is not a must. If you want suggestions here provide a lot more info please.