Brighton hade the 4th most possession of any team in the PL last season. 53% at Stamford Bridge to give one example. So yes, there's been plenty of low block defending teams - and in Brighton he has struggled with it. Chances have been created, lots and lots, I suggest you watch this from the 2020/21 season:
In Swansea and Östersund, this was not a problem. In both of those clubs he had access to a strong player up front that would create spaces for midfielders and inside cutting wingers, often through moving towards the wings to pull out defenses and get into easy aerial battles with short full backs. Other than that, his teams create chances through superior movement and bravery. Patient play until there is a trigger - an opponent going into press or a combination of movement within his own team - and then try to make quick, slick combinations into chance creation.
It will come for you eventually, but it will take time, that much is clear from today and your starting lineup will look very different in a month or two - it is clear that some of your older players doesn't have the required physical capacity to play the way GP wants football to be played.