Surely a combination of blocking runs, 1 or 2 of our tallest players whose sole job is to attack the ball and the rest zonal would be better. The problem with man marking is that to do it effectively you have to foul attackers (holding them, grabbing shirts etc) which VAR will pick up on.
There was also some very good analysis on MOTD yesterday of our inability to block crosses in open play - there were 2 half arsed efforts by Biss and 1 from March which were highlighted (our goals conceded from crosses stats are crap too). We are not getting tight enough essentially, which should be easily fixed.
It's all causation, if the cross is stopped, the corner may not be conceded and the defending or lack of doesn't happen.