this is a unique political conspiracy theory in that both sides are convinced the other side did it. alt right people are convinced this was some kind of cover-up because bill clinton was closely linked to him, and left wing lunatics are convinced it was trump that ordered it, because he had close ties to epstein.
bottom line is, killing yourself in a federal prison/detention center like MCC is incredibly difficult. he was on suicide watch very recently (not sure its been confirmed he was on suicide watch when this happened), and because of that, he should not have had any access to any material that could be used in any way to assist in his suicide.
if the investigation is bad for trump, its obvious that barr will squash it. depends if any of the material witnesses or people who know what happened speak out of turn or leak