I'm not so sure Dementia Joe knows yet exactly what his party plans to do to us.
Here in MA, we have some interesting challenges re: hi-cap magazines, loaded or otherwise. Right now, they must be pre-ban (pre-1994) to be legal... and pre-bans tend to be very expensive. So what happens once Uncle Joe gets done with us? Will Federal law trump state law? Or will state law trump Federal law? We here behind enemy lines might actually benefit if a new Federal law wipes out the various state laws... although I'm not going to hold my breath on that hope.
Concerning loaded magazines, MA has a regulation that requires ammo to be stored in its original containers (meaning original factory boxes). So are you in violation if you load a bunch of 30-round AR magazines and store them that way long-term? Technically, yes... although you might have to look hard to find any gunowner who really cares.
I'll admit that I don't generally store my magazines loaded. I probably should, but I don't. Just a personal preference.