This is from the steam announcement on the subject:
To our RPG Maker Users,
Due to Apple deprecating OpenGL support and other additional changes such as removing support for 32-bit software, RPG Maker MV has had many compatibility issues with the latest macOS updates.
As we are sure you are...
I was going to add, windows updates or even steam updates often make CPUs run slow. I got 2 fps once in an RPGMaker game due to windows doing a 'background' update. Needless to say I was not happy.
Closed as solved.
It pops up the damage valuesit takes for me automatically, though just as a normal damage popup. But that is with Yanfly's Battle Core and Yanflys popups too, as I set it up to send the command to the popup from that engine.
I never really got a chance to code it with other battle engines sadly.
I've made a lot of small changes and fixes over the past couple weeks without actually making any progress on my game...now I'm running out of things I want to change, and I'm terrified that I might have to start being productive again...the horror! D: