In the past, I have pasted an address into contacts and it would automatically populate individual fields.

In macOS you can copy a complete address and have it paste into individual fields, but only if Apple likes the format. If you copy an address, verified by the USPS website, like "2336 W STATE ROAD 434 STE 678" and try to paste it into the street line on a new contact, it will not paste, you must manually type the address line. You can copy it to notes and then manually type the address but "2336 W STATE ROAD 434 STE 678" can not be pasted into a street field in Contacts at all. Using macOS 26 contacts, try to copy "2336 W STATE ROAD 434 STE 678" and create a new contact. It Truncates it to "2336 W STATE ROAD" then you must manually type the rest of the line. If you change Road to route, it handles it differently if you change the "434" to "43" it also parses is differently.

If you copy "123 Main St, Nowhere, NY 10067" and paste it into contacts in macOS 26, it will place each item into the proper field. A little bit of testing can show the issues, not so easy to fix I imagine. Note these addresses are fake, but the actual business's address I had the problem with was not. The actual street name "W STATE ROAD 434" in Longwood Florida is where the problem lies. Also, note although contacts does not recognize "2336 W STATE ROAD 434 STE 678" as legitimate, Apple Maps has no problem with it...

Since "Apple Maps" doesn't even use the same Address format as "Apple Contacts", I guess it will be a long time.

Also note, iOS will not parse any addresses when pasting the way macOS connects does. It just places everything copied onto the address line when pasted.

I believe that it should not be an issue to have everyone use the same addresses. USPS, FedEx, UPS, Apple, Microsoft, the fire department, county property appraisers, etc. For instance, an address on Apple Maps used to mail a letter, won't be necessarily understood by USPS.