No 90s teams could adapt with a flick of a switch to a series setting during this current day. That includes the mid/late-90s Bulls squads. It would take time. Jordan wouldn't be used to having all those lanes cut off to the paint, he wouldn't be used to dealing with not having his patented weakside ISO play as the foundation to his production, the Bulls as a team wouldn't be used to going from trying to beat man-to-man defense to having players rotating and helping at every point on the floor.
Ball movement and player movement. Hand-checking wouldn't affect the Warriors offense because they don't work through ISO actions.
It was less about the physicality aspect, and more the type of defense in which the Cavs were playing. Swarming Curry and shutting down his options by leaving their matchup unguarded and staying within the closed points of the perimeter - defense which was illegal in the 90s.
Thing is the Bulls could use tape and practice and previous experience with zones to prepare for zone defense. It's not like this would be their first time dealing with zones. They all have experience in college or at the international level dealing with zones. You can't really prepare for a greater level of physicality if you haven't experienced it before. These guys didn't grow up playing like that. Tape isn't gonna help you. You can't practice at the same level of intensity that the game will be played at. Players aren't gonna move the same if they are getting grabbed and pushed and hit, especially if they aren't used to it.