He's setting up a go at the presidency. He knows that the DNC will want him to lean conservative, but he doesn't want to be painted as flip flopping or pandering, so he's leaning into it early. Now when the GOP inevitably calls him a woke far left extremist (or whatever buzz words they're using by that time) he can point back to this period as proof that he's "always been a centrist" who can appeal to non-MAGA conservatives.
Of course, he and the rest of the DNC haven't figured out yet that conservative voters are NEVER going to vote for the LESS conservative party.