Yeah, honestly, the part of DMing that always slows me down the most and is the most aggravating to deal with... is HP when dealing with a large group of monsters. Remembering which orc is Orc #4 and subtracting the damage is the part I mess up the most and is the hardest. Status effects are usually a bit easier. "Oh, this guy can't do this thing"
I always use a little portable whiteboard to track and and then paint my minis with unique colors sometimes just painting the base a color or two. That way I can easily distinguish between yellow + green zombie and blue + white zombie. For status, we have markers. But truly large groups of monsters? Those become mobs, even if I don't use them very often.
But everybody has to find their own groove.