I don't think you're doing a bad job as mod, if that counts for anything. But here's my two cents from my previous experinces as mod and in knowing mods on an old account of mine:

Never call out a user in a post like this when you're a mod. It doesn't bode well for anyone and in my opinion at least, is wrong to do as a mod. I've had this talk with other mods and I understand where you're coming from, but it's best not to call out another user unless they are directly attacking you and you're addressing the things they've said.

Harassment is just being a general jackass to everyone. Sure, some things can be tolerated and will only be downvoted. But insults add up over time, and if certain users continually insult and act generally like assholes to people, they should be warned and then banned if they refuse to change. Temporary bans are also a thing, give them a week breather and see if they change their attitude. I don't care how important someone is to the community, play by the rules and generally respect the people on the sub unless given a reason not to. If you can't abide by that, it's better to leave.

I'd add a rule that has worked for other subs far larger than this one: Don't be a dick. Sums up what most people are talking about.

Like I said, you don't have to ban, only warn. If warnings aren't working, temporary bans. Otherwise a permanent ban. And people can always apologize and you can give them a second chance too. But there has to be some discipline for those out of control, and I think we've all seen some issues in this sub with people continually being a bit out of control.

For a sub like this, I don't feel the ideals of "free speech" are that important. If they were, I could post a whole bunch of unpleasant slurs and that'd be cool? Well being a dick repeatedly to many users isn't okay either. Not that you can't hold up to those ideals somewhat, but it doesn't mean you have to tolerate someone just being a jackass either.

I know my whole shtick about Don't Be a Dick seems vague and it is. It gives you more control whether you want to enforce something or not, and also makes a good case for people to be able to appeal your decisions in modmail.

Also, picture this: If someone were to be making a lot of these comments being considered "harassment" in real life, they'd be told to fuck off on the spot and no one would tolerate it. Do it online and it's okay? Not in my opinion at least. I know, perhaps, that's a controversial opinion, but if it would be considered harassment, being a general dick, or straight up bullying in real life, it's the exact same online too.

I don't think the issues are too hard, you've already begun to work on the "just search for it" issue. Beyond that, it's stopping what has obviously become a problem, the general asshole attitude towards many users being put forth by some members. Unfortunately, people won't use the report button often. At least in my experience.

Anyways, hope it gets a bit better for you, I appreciate your maintenance of the sub and I understand the stress of all this.