How are blobs stored in row_format=dynamic in overflow pages ?

Since the change from MariaDB server 5.5.57 to 10.3.18 the errorlog now contains messages like:

2019-10-04 6:21:40 10 [Warning] InnoDB: Cannot add field `EventAttributes` in table `zissystem`.`eustatus00000101495_history` because after adding it, the row size is 8483 which is greater than maximum allowed size (8126) for a record on index leaf page.

Can this message be suppressed ?

As far as I understand this message means that the row_format of the table has to be migrated from 'COMPACT' to 'DYNAMIC'. In the table are contained 9 blob columns.
What does this mean for the used table space if the table uses row_format 'DYNAMIC' instead of 'COMPACT' ?

Does this mean that if each blob is filled with data that 9 overflow pages a 16kB are used ?