Hi Panagiotis, thanks for this proposal.
I don't have a strong opinion (yet) on whether we should allow to indent to a custom column by setting org-adapt-indentation to an integer. My gut feeling for now is that this is too much, but I don't want to dismiss this possibility completely. That said, the new customization values for org-adapt-indentation have not yet been released, so I suggest continuing the discussion for after 9.4 has been released and for after org-adapt-indentation has been more widely used in its current (from master) state. Thanks, -- Bastien