I’m no historian, but from everything I’ve read Jefferson despised slavery and wanted to see it end.
That is my knowledge as well. (if/when it came up. Slavery was NOT the biggest issue of the day)
Early years as a legislator. Anti slavery
Declaration author. Anti slavery (even if, by the hands of others, it is removed. HE, Jefferson, did his job. Consistently)
Years as a governor. Anti slavery
Years as president. Anti slavery
Years in between as negotiator, advisor, activist, author, and other scenarios:
Anti slavery.
I have never seen anybody produce at any time any instance where Thomas Jefferson placed himself on the side of defending and even worse, promoting the goodness of the institution of slavery. But conversely, time and again he works - however futilely - against it throughout his entire life.