Disagreement is maybe best communicated by the absence of an upvote?
There is a quote "You can not not communicate" but on the internet you can. If I get no upvotes, I don't know if no one has seen it or people actively ignored it and it's a bad advice to feel disagreed on when no upvotes.
I personally feel frustrated when I get downvotes but no comments because I don't know why I'm downvoted. Some instances here in the lemmyverse (like mine) don't have downvotes enabled so I don't even see downvotes.
I think it's best to engage in a conversation if you disagree in a constructive way and downvote without comment if you feel this is beyond help.
I'd still very much like to HIDE threads I'm not interested in. Otherwise, no matter what stream I choose (Subscribed | Local | All), I keep seeing the same topics, and it can be downright difficult paging through streams to see new stuff from more communities. That's not good, frankly.
You can choose a sorting algorithm. If you sort by "New" you get the new stuff but you can also sort by active, new comments, ... to get variation.
At least in Jerboa, there is the account setting "Show Read Posts".
I hope that's helpful. I'm pretty sure it exists but I haven't found a history function. I'd like to have a list of the last posts I've visited.
This must be the progress everybody is talking about