Yea there’s a 16mm version that’s a small filesize (which is on myspleen), whether or not that’s the one on either the stinkytuna blu reviewed on youtube or the “2021 version” DVD is anybody’s guess.
The “2021 version” DVD can’t possibly be better than Notelu V2 on archive since it’s DVD sized (whatever version they may have used for it).
The stinkytuna blu is described as the Japanese laserdisc by the youtube review (though seems odd given that there are no burnt in subs during songs) and is described as a “16mm film print” on the songofthesouth.net review. A good guess is that it’s not better than Notelu V2.
Whether any of them is better than Notelu’s version depends on the restoration. There is always a chance that Stinkytuna or the one who released the “2021 version” did further cleanup or color correction to make it look closer to an official release. However, I personally would not spend money on a release that, in 2021, claims that Song of the South will never be available in HD when it has been available since 2018.