When I include a long-term collectible I sold, it makes my tax due at the ~35% tax, which is similar to my regular income. Why isn't it taxed at the max 28% rate?

I have a fairly high income at ~$200k annually. I sold a high dollar collectible for ~$150k.

My withholding is setup correctly for my income, making my tax due ~$0.

When I include the collectible and check the “collectible” box, it makes my tax due ~$54k at ~35% tax, which is similar to my regular income. I thought collectibles were taxed at the max 28% rate. Any idea why it would be taxed at a level similar to my regular income? Collectable was held for around 3 years.