Every stadium I've ever been to has taken ages to get away from with mad crowds. Spurs, Arsenal, Wembly, Goodison, West Ham (old and new), Brentford (actually not so bad cos it's tiny and near where I live) etc etc. There's no magic way to get 50k ppl all away from an area quickly and easily.
This.
Any modern ground not in a naturally built up area is dreadful to get out of. None of them have a load of different public transport options and actually for a modern stadium, being a 20 minute walk from town is pretty good.
The lack of infrastructure around the ground was the price to pay for a stadium on the waterfront.
A more agile council would have done something about Sandhills (actually doing anything about sandhillls isn’t something we are set up as a country to do never mind a council) and other public transport (a load of busses into town/wirral etc from the dock road would help).
But unfortunately the egress from the stadium site is probably something that will have to work itself out organically at this point, it might be crap for a season, but it will be worked out.