If you adapted the work licensed under Creative Commons licenses, you must indicate this.
indicate if changes were made — In 4.0, you must indicate if you modified the material and retain an indication of previous modifications. In 3.0 and earlier license versions, the indication of changes is only required if you create a derivative.
https://creativecommons.org/licenses/by/4.0/#ref-indicate-changes
I don't think that SPDX-FileCopyrightText or SPDX-License-Identifier alone can satisfy this condition.
What's the best way to achieve this with REUSE? Is it correct to use SPDX-FileAttributionText?