Brighton is not an easy opponent for Liverpool, although Liverpool's percentage of winning the match is much greater, but anything is possible and nothing is easy for Liverpool to get 3 points.
The match between Manchester City and Arsenal is a match between two teams who are competing for the title, so indeed both teams will target victory in this match with the same ambition, so with the teams' strengths being balanced, this match will be very difficult for both teams.
Even while trying not to undermine Brighton, I will still not see them as been a rough team against Liverpool, they don't have what it takes to contend Liverpool to a victory, regardless of how much resistance they may put up in that fixture, I still doubt if they will be able to win or steal all the Three points from Liverpool, they can manage to get to share the point equally with Liverpool but they will definitely not going to stop Liverpool.
Taking a critical look into Brighton's performance since this season, you will find out that they aren't consistent in their performance a d results, they even got to a point they weren't productive enough and they have struggle to maintain a position away from getting down to relegation, with too many inconsistency in their performance, they are not sure of qualifying for both premier or champions league next season, they are not a team to be compared to Liverpool in any form, even going by the quality of the team too, they are not equal with Liverpool.
Their depth isn't any where close to that of Liverpool a d they don't have same strength tok as Liverpool as I still strongly doubt if they will be able to challenge Liverpool to the point of becoming a problem to Liverpool or even winning Liverpool by the end of the day but then if they are able to get a draw they have tried but considering whats at stake, I doubt if Liverpool will be kind enough to give room for such to even take place because Liverpool need every of the opportunity they will be getting.