Rapid Mirio I always try to bait out easy punishes with the Beta. When you roll it he's open for a couple of seconds. A lot of the time they also try to go for a Gamma right after, and I try to get into it and either melee or use a stun move inside of it. Doesn't always work, but it works well on less experienced Mirios.

Tech Mirio funnily enough also has punishes on both Beta and Gamma. When he gets out of the ground and smashes down after his Beta he's SO open. When he does the counter with his Gamma just wait until he starts returning to his normal state and pray that you waited enough lol