They had a backup that incredibly also had a "technical problem".
"Jail CCTV erased by 'technical errors'" - https://www.bbc.com/news/world-us-canada-51053205
That seems like the only remaining "plot hole", from a technical perspective.
https://www.businessinsider.com/jeffrey-epstein-jail-cell-fo...
"FBI studies two broken cameras outside cell where Epstein died" - https://web.archive.org/web/20200622111206/https://www.reute...
You should make a new account titled "PlausibleDeniability".
At the very least, a very persistent Devil's advocate.
I have seen enough Law & Order episodes to know contract killings are always done by a prisoner already inside the wing.
As this was a prisoner know to cajole with a past US President, and also the current US President at the time, a professional and competent police investigation would take it further.
Like say...Could it be possible the cell of another inmate was left open by accident? Any other inmates present at the time known to kill people by strangulation? Tracking the bank accounts and private life of the characters closely related to the events at the time? Like prison guards, lawyers, prison administrators and inmates? Anybody suddenly taking trips to Dubai and Vegas?
From what I've read that was debunked. Initial reports said two cameras could not recover footage but one of them was later restored. No one know how long it was malfunctioning. No cameras were ever pointed at his cell, these were just cameras in the vicinity and there was plenty of recovered footage for the corridor showing that no one approached his cell