Yes: Filter is a Sync feature, Block is a Lemmy feature, and the block list is tied to your Lemmy account.

If you only use Sync to access Lemmy, then both are practically identical, except for the number of clicks you need.

Trying to block hexbear?

This 100% this please

I very much agree. Infact I think that the Lemmy block should supercede the sync block. Filtering this way means that nothing is blocked when I'm on desktop