mkxp VS Player

It depends on what part of Easyrpg you're trying to replicate. If you mean that you want the games to run less crappily on modern systems, and/or you want multi-platform support, then yes. There is mkxp and mkxp-z. However, it's not exactly a plug-and-play solution, and it's something meant to be implemented by the developer of the game, rather than the players themselves.

You can use XP if you like; just use something like mkxp to get modern app behaviors.

You can play them with EasyRPG Player, the fps varies game to game

I had a similar issue before. I think it had something to do with the fact that people used to make games on pirated versions of 2K3, so there are multiple versions of the RTP floating around and stuff. In the end, I just wound up downloading EasyRPG Player. Just dropped Player.exe into the game's directory, and used that to execute the game (instead of RPG_RT.exe), and it worked like a champ.

quick search says it works with that: https://github.com/EasyRPG/Player

Otherwise, you can also try EasyRPG. I think that would negate the need for you to install the RTP in the first place.

Grab yourself some copies of EasyRPG Player!

Sounds like you're trying to play an EasyRPG created game. Those files need be run through the EasyRPG player.

Oh, never mind that, I can't wrap myself around MacOS. You've gone through so much effort. Use EasyRPG player for the 2000 and 2003 fangames.