Allow creating a proper based on another one.

I have multiple condos in the same condominium, so most of the information is the same.

Would like a base property and then create properties based on this, overriding certain fields and being able to add to it. Like additional photos of the actual condo.

Another way of looking at this is to have a template property, you can base other properties on. Making changes to the template and the properties based on it would pick up the change would be the best. This is knowing what was overridden would help.

Would duplicating that main property work for you? Once duplicated, you can edit the differences. This article gives more details:

https://www.ownerrez.com/support/articles/add-new-property#duplicate

That is what I did. The problem is not all the fields were copied and rooms and photos were missing. Ended up just importing multiple times from AirBnB.

Then making changes that apply to all of them.

Just suggesting IMO would be an improvement.