I agree that the match between Roma and Brighton will be difficult to predict as both teams have similar strengths. However I believe that Roma has the edge in terms of experience and recent improvements under De Rossi coaching. Their performance in the Europa League and reaching the final last season shows that they have the ambition and mentality to succeed again this season. I think Roma will have a slight advantage in this match. So let's see.
There's nothing like taking home advantage, because the current epic moment of football differs, have you not seen a situation where the home team becomes the one to suffer humiliating loss. For instance, Sassuolo hosts Napoli and ended up losing 6-1. The same scenario happen between Luton Town and Manchester City, where the Citizens mercilessly flogged Luton Town at Kenilworth road. We usually understand the Europa matches and it becomes more interesting at crucial phases this season. The game fixtures fixed between AS Roma vs Brighton & Hove Albion becomes tougher and unpredictable. Expect we will be settling for GG from both sides, there's no way both team will nets at the back of the nets.
Playing home or away shouldn't have a big impact, only the support from the sportsman makes the home team's confidence the difference.
However, for the Roma vs Brighton match, which will be played occasionally and also away, each team must have its own strategy and in my opinion the most important thing is the quality of the team and if we look at the quality of Brighton and Roma there is no significant difference so this will be a match that difficult to predict.