If I was Liverpool I would try to keep Mo Salah for a few more years instead of trying to replace him with another expensive player and instead I would put 2-3 promising young cheap players under his training and at least one should hopefully be able to learn from him and one day replace him. That would be the best thing the club could do in my opinion and they would save or even earn a lot of money.
There is no ground on why Liverpool will want to keep him, he is winning the Premier League and that's cool but this is not his first with the club, he has won it before. My suggestion would have gone to Balon D'or if they have won the Champions League but they didn't even last immediately the knockout stage, they couldn't win the EFL Cup, his chance of winning the Balon D'or has reduce drastically because how is he going to win it with just the Premier League.
There are more things to explore than only the English leagues, he can try Saudi like his dear brother, Mane is there and he is making his money without the media thing, he will get paid more than he is earning in Liverpool for sure. If he decide to stay back in Liverpool, he should know that he is doing it for the passion but the money won't come or increases and the chance of winning the Balon D'or have reduce because this Premier League table wouldn't be the same next season.