Yes I think hardly anybody thought that Liverpool would be standing where they are after Klopp left the club. But to be honest Klopp left a team behind that was so well coached and prepared. Now since Slot was totally unknown, I thought that the team spirit might decline significantly, but he managed to keep everyone in shape and they play an impressive game. If they score a goal, it is so hard to fight back against them because as you said their counter attack football is so effective. And Salah is still doing so well. I thought he may have had the best years of his life under Klopp, but he is still world class level.
Slot replacing klop initially came with too many uncertainties as there were some kind of doubts if he's capable enough to carry on with the legacy of klop, but as time goes on, we see that klop did left Liverpool in a very good and safe hand, they are doing as good as they have done under klops management, some persons including myself never taught of Salah still this optimal at this point, but interestingly he's not passed his performing prime just yet and Liverpool still have the potential to scale further heights this season and probably beyond.
Slot has done an amazing job in maintaining Liverpool momentum after Klopp departure, although this season is his first season coaching, but he is able to bring an effective approach to improving the game that Klopp has built before, although it may be too early for us to say if slot will be able to match Klopp achievements at Liverpool, but at this time the probability of bringing Liverpool to EPL and UCL champions is almost 90% in my opinion, his ability to optimise each player is key in building Liverpool to be better.
Salah has shown that age is not a barrier to keep performing optimally and consistency in scoring goals.