It doesnt appear there are ownership transfers since he bought it last year, but the site is now funded by the Biden for President organization as of july this year, after Steyer's failed attempt last year to campaign for POTUS. July is shortly after
Steyer endorsed Biden. Although its impossible to tell who the actual owner is at this point, it is likely still owned by Steyer, as domains are usually bought for 4 year terms. The current IANA info shows the domain is active through June 2023, which would coincide with a 4 year lease from 2019.
That said, if you look at the website after Steyer bought it in 2019 vs the domain now, its essentially the same (anti-Trump). Likely the Biden for President organization is paying for it, without a change in ownership. The owner, who we know was Steyer as of last year, is hiding behind the registrar, GoDaddy.
That said, I need to walk back my statement of Biden doesnt own it (I mean, he doesnt own it personally, but his organization is certainly paying for it). But my comment regarding Trump never owned it are still true. Thats verifiable via archive.org.