When modifying the table's columns default input field is disabled for columns that are the primary keys. At the same time, it's possible to work around this (by enabling the input) and provide a default value.

How to reproduce?

I created a new table with a UUID field, which is also a primary key.

Then I wanted to modify default value for this field, but it is disabled in the UI:

So I removed disabled from this element:

I provided gen_random_uuid(), and successfully saved changes: