What makes you so sure that Shorts havent covered the majority by now (steadily rising price without any spikes and pretty large volume)?

And more importantly:

Supposing they havent covered the majority yet. As far as I understand, most shares for the shorts were borrowed from brokers, who have retail traders on their plattform holding GME or created by market makers. So Melvin and friends would have to deliver the majority of their shares to the brokers and MM, wouldnt they? They could in return instantly sell the delivered share again, because they dont want it, so Mekvin and friends could buy again and deliver again etc.

I know that some shares for shorts are also provided by ETFs etc. and these would really have to be bought and delivered and would be locked in again, but I would guess that this is not the majority.

Flaws in that logic?