Anarchy Reigns and next up Fist of the North Star.

Double Dragon Neon even though its a bit on the hard side if you play it solo.

I don't see a meaningful distinction between them.

Agreed, Hack ' n Slash games are just weapons based Beat 'em Up games.  Also many Beat 'em Up games also have temporary weapons which makes the difference even smaller.

I was gonna say bayonetta... then i remembered it was havk n slash.. then i got confuse what is the difference between the two T_T

Fighting Force for PSone was a good beat em up. It's very similar to river city ransom. I can't think of anything after the 1990s though, let alone 2006 onwards.

Yeah, according to Nicalis, it's 2 player local co-op in the campaign mode.

https://nicalis.com/games/code-of-princess-ex

You have to gain characters along the journey and I guess the 2nd player chooses from them. I don't think there was multiplayer on the 3DS version so this must be a new feature. 

Yeah I've seen that game before, haven't gotten around to it. Reminds me a lot of the Streets of Rage games.

Another good beat em up on Switch is, Gekido Kintaro’s Revenge. 

https://www.youtube.com/watch?v=mLpoZAQly_w

It's kind of like the River City Ransom games but more focused on story. I recommend it. 

Of course this comes down to opinions in the end, but to me there is a distinction and they feel different. There are many ”weapon based” beat em ups (golden axe, DnD:Shadow over Mystra, TNMT to name a few).

I think that, at least for me, one distinction between what I consider a HnS compared to BeU is the amount of enemies you can engage at once with normal attcks. Most of the games I consider HnS you regurlarly hit hordes of enemies at once. In BeUs you hit one or two at a time and maybe you can throw an enemy at another one once in a while, this regardless of how many enemies there are on the screen.

Charlie Murder was a notable release.

Thats the only game I can think of that has not been mentioned.