It's so good, but so hard. Here's something that has helped me recently. I start a local Team Deathmatch, join red with a training sword, get into a corner next to a supply box, and then ` to get console and "AddBotsTeam 2 1". It's really helping me with my double parry/chain parry and keeping my vision processing more than 1 attack at a time. I'll then give myself a real weapon and have 4 enemies at a time from the same place and just try to survive.
Ya, HEMA would be dudes in modern plastic protective gear, maybe wearing a gambeson. Some people who do both would sometimes use metal gloves, but never a full set of armor.
Generally just called re-enactment if it's supposed to be a strict representation of the battle. There are lot of Civil War re-enactments here in the US, and some of them get pretty rigorous, timing things down to the minute as they happened in the course of the battle.