After reading details in the indictment, it’s pretty clear why the two attorneys resigned from the case: They were lied to by Trump.
After reviewing boxes in the storage room and removing classified material from them, Trump attorney 1 (either Trusty or Rowley) directed Trump attorney 3 (likely Lindsey Halligan) to certify that all such material had been removed and accounted for. What none of the attorneys knew is that Trump had directed Nauta to remove and conceal other boxes of classified and/or national defense material from the storeroom to other locations on the property. This material was discovered during the August 2022 FBI search.
Having both been lied to and subject to being called at witnesses by the DOJ at trial, they no could longer represent him.
Re: 79 - I am plodding through the charging document, but the reading so far suggests your take may be on the mark.