I don’t know about the sorting (I think it’s just based on engagement), but downvotes have no effect on your account

Idk about the negative points question, but karma in general doesn’t exist here. Your comments and posts get quality scores determined by the votes, but that is mostly detached from your account.

Screw the internet points. Even when I was using Reddit, I use Ublock Origin to block the karma point next to username top right, no point, no distraction.