Sapflow frmo the roots to the plant goes through the trunk. So removing the back does not do anything there. But sapflow from the leaves to feed the roots is in the bark. Effectively, you are reducing transport options to the roots.
At this point in time you should let the plant sort itself out and not fiddle with it. Especially such thin branches do not have a huge amount of reserves. Let it be. Olives roots well from cuttings, also if you would have had big branches, and therefor there should be no issue.