We had barely started liquidating assets when our offer got accepted, and it added unnecessary stress to the process.
It really depends on what you're liquidating. Personally I started liquidating around 2 weeks before closing date, but that was also a full 2 weeks after offer accepted. The weekend after our offer got accepted, I walked through the timeline with my agent to really understand when funds were needed.
I had the funds for the good faith money already, but the down payment (we all know how big they can be in the Bay Area) needed stocks to be liquidated and funds to be moved around. We backcalculated from closing date and when funds should get wired and worked our way back to the last day our trades had to execute including some buffer time.
If your assets are more complicated than just typical stocks and bonds, then it may require extra time, but I think if you plan well, you don't have to liquidate right when you get your offer accepted (assuming you have your 3% money ready).