These are my takes on alternate Sync logos for Lemmy (I made that rat from a while ago)
The logo for Sync is so tied to Reddit for me personally, that it was hard to think of ways to translate it to Lemmy (or the Fediverse overall).
Orange and Blue are signature colours for Reddit, but Lemmy doesnt necessarily have a colour scheme. Nor should it. that's up to the instance operators to choose, making their community unique.
I also like the general Fediverse pentagon logo, but it can look quite busy...
I did what I could. I'm an average designer at best ¯_(ツ)_/¯
Middle left, if it's to similar with just the color change then go middle right. Middle right has a clean simple look and good symmetry.