Border control...There is a strong push amongst actual leftists to open our borders completely

Who is saying that? Right-Wing Media? There is no significant movement to completely open our southern border, nor is it something the current administration is demonstrably moving toward. What is happening is right-wing media creating a strawman in bad faith to misrepresent liberals opinions on the southern border. For example, not wanting to build a border wall doesn't not equate wanting an open border. Just like not wanting to buy a Suburban doesn't mean I want to walk to work. The border wall has been a thirty year grift that Republican politicians use to line the pockets of their donors through bloated contracts. Republicans have controlled the Presidency for 12 years over the last two decades. Why wasn't it already done? If you look into it, you'll find significant logistical issues including there being a river and terrain that isn't friendly to construction. There are areas where an existing wall cuts off US Citizen's farms and ranches, and where Border Control can't easily get to. Then there's the topic of Circular migration where preventing some migrants from leaving would double-down on your social services problem you mentioned.

Another one would be the police abolition movement. I think there is good reason why every functional country on earth has a police force.

This one again is not in any supported by any politicians or most people. "De-fund the Police" is a poor slogan any way you look at it. Yes, there are people that mean in literally. I can't blame them. The truth is there are areas of this country where the Police act more similar to organized crime than a protection force. This is not literally true the vast majority of the time, but you can't go 2 days without hearing about a situation where there's corruption, or unneeded escalation that causes another civilian death. The movement I'd like to see is to Reform the Police, but that doesn't really sound great in a protest march does it? Police should de-escalate situations, not escalate them. We hear these stories of mentally ill people who are not violent getting shot because someone calls the police to get them help, and the responding officer starts yelling with their gun out making everyone nervous and the mentally ill person gets shot. Or we see stories of overreacting to children, even arresting them for minor disobedience. We see an "us vs them" mentality coming out of the Police where they refuse to hold their own accountable. All of these things should be agreed upon universally imo. I've said this to some Gun-Loving friends before. Why should "he had a gun" be a reason for a cop to shoot you dead without getting your day in court? Last I checked conservatives are way into the 2nd Amendment, so this universal love for the Police, especially when they do wrong is puzzling to me.