System was fine vs Chelsea. Issue was a pathetic penalty given away by one of the midfielders and a lack of a striker.
Why was that midfielder there? The system says that he should be. The personnel available to us at the time however struggle to function in that system.
The lack of a striker was known beforehand. We then picked a system that asked a lone target man to do a lot of hold up play, but deployed a player who cannot function that way in that position.
To succeed we need to use a system that maximises the strengths of
our players and minimises their weaknesses. The 343 does NOT do that, because we don't have any midfielders who can play in a 2-CM structure apart from maybe Onana.
Most of our current squad fits a 433 best. We should either play that system, or recruit the correct players for central midfield to adopt a 343. What we SHOULDN'T do is try selecting Davies, Doucoure, Iwobi, Allan, Gomes or Gbamin to play CM in a 343.