Hasbro has started uploading official versions of The Transformers episodes to their “Hasbro Pulse” Youtube channel:
https://www.youtube.com/c/hasbropulse/playlists

Have only checked out a couple episodes, but this might be the best quality yet, with a few caveats:

Episodes are upscaled to 1080p24 (1080p23.976 to be precise), not new HD remasters from film
The video seems to match the Rhino masters rather than the Shout masters, which means that Season 1 in particular is better quality, but there are additional animation mistakes not present in the original broadcast masters (Skywarp/Thundercracker being colored like Starscream [or vice versa] more than usual, etc.)
The audio thankfully does not have the added sound effects from the Rhino DVDs
There are less jaggies than the DVDs, but they are still present in some frames due to the occasional ITVC error, so the masters are obviously 480i rather than directly from the film source that Rhino used for their DVDs
apparently the same versions used on other streaming services (Tubi? not sure), but I haven’t checked to see if they have a higher bitrate or anything