Trump doesn't need to unseal anything. All Trump has to do is nominate a new National Archivist. Obama's very first act in office was to sign an EO defining how Presidential Records requests are handled. In short, the National Archivist notifies the president and gives him 30 days to respond as to why he would want the records to not be released. It ends to be noted that Obama also put a new Archivist in place after the previous archivist magically resigned over an unnamed scandal in DEC 2008, just after Obama was elected but ere he took office. In 2017, after Obama left office, the scandal was revealed to be a sex scandal. That same Archivist is still in place. With a new Archivist who isn't loyal to Obama, simple requests for things like college transcripts, which do not impact National Security whatsoever, should be accepted, even over Obama's objections (after 30 days).
Pres Trump, this is a very easy fix.