I don't have any. It's my #1 go to news source

HNRankings helps: https://hnrankings.info/

Not being able to block posts or comments by some users.

I routinely fat-finger the hide button while browsing on my phone. I then need to fish the article out from somewhere within my profile.

And fat fingering down votes.

Accidental downvoting is also easy on mobile website. I zoom in each time just to be sure.

Same; really wish they’d increase the target sizes on mobile devices.

Groupthink and heavy pro-establishment bias

If there was too much transparency marketers would try to game the system. It works well enough the way it is. But I have observed that stories in which the comments are unproductive or too heated tend to rank lower.

I don't buy the argument that transparency will bring abuse. Transparency can actually make it easier to understand and mitigate abuse because users and moderators will know what to look for. The benefits, such as increased trust and better quality content, far outweigh the potential downsides. Clear guidelines (how the algorithm actually works) can help users create more valuable content while still allowing the system to adapt and respond to any manipulative behaviors.

Just found one.

Haven't been able to search Show HN in a thorough timeline, in order of submission, starting with current submissions going back very far at all.

"show" doesn't do it, "past" doesn't either.

Will be nice to have option to search at own bookmarks only

If there is a downvoting feature (which I consider contraproductive), there should also be an "unflagging" feature.