I'm gonna necro this thread.. it's still the same in FM24. I've been aware of the red card = better AI for years and years and I've tried everything to combat it. Formation changes, attacking mentality changes (both ways), shouts of all flavours. I've even taken advantage of it occasionally myself... game is level, I lose a man, don't change anything significantly and win the match.
Long story short, nothing works. It's bollocks that losing a man can't be reliably exploited.. actually the opposite... it's damn hard to even maintain parity!
If you go a man down IRL, you don't expect to outscore the opponent (which happens regularly in FM). Please figure out why this happens SI.. it's not a rare occurrence and needs addressing.