No, they didn't set this precedent.
HRC conceded the '16 election within hours of the race being called, and called to congratulate Trump, which Trump hasn't done to Biden and probably never will.
She didn't file 60+ lawsuits or send lawyers to hold deranged press conferences full of conspiracies. Obama didn't block transition funds, didn't call up his Democratic friends in swing states in an pressure campaign to throw the election for Hillary, didn't instigate an armed mob and send them marching toward Congress.
A small number of progressive House Democrats objected to the '16 election, but they didn't have institutional support or the support of a single Senator. Then-VP Joe Biden himself conclusively stated: "It's over."
https://www.allsides.com/blog/past-electoral-college-vote-objections-democrats-explained