I think part of the problem is not necessarily the full backs, its the wingers(wide midfielders) not helping out so the full backs get exposed.
Successful 4-4-2 formations would have the right back/winger working in combination both in defence and attack. Our 4-3-3 / 4-5-1 or everyone chase it formation leaves us exposed at the back.
As mentioned on this board in other posts we don’t have successful partnerships anywhere on the pitch.
Maybe thats why Figs is looking ropy since Martinez formation came in cos Hugos never there to help him?
But what do I know??