iMac 27"

Correct; Apple doesn't sell 27-inch iMac models in "new" condition.

However, you may be able to find one on the Apple Refurbished store that will suit you needs. Currently, there are many 27-inch iMac configurations available: Refurbished Mac - Apple.

Additionally, if you wanted a 27-inch display in a new Mac, you could purchase either a Mac Studio - Apple or Mac mini - Apple, and pair it with a Studio Display - Apple.

Jack

Apple no longer markets a 27” iMac. You may be able to purchase a refurbished unit directly from Apple if a 24” doesn’t meet your needs.