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)_/¯
It's also more obvious that it's constructed from the arrows of the original logo, compared to the middle bottom one that's more overlapping/intertwining.
It was either focus on the arrow motif or Fediverse symbolism.