Liverpool to me have oversold their players in this transfer window and for the fact that the session is around the corner makes it more obvious that the club may be taking a rather hard route this time because just as you rightly said getting a replacement for those players will be a tough quest for Liverpool.
And if care is not taken, Liverpool may have a bad season again in this premiere leagues, even though the previous season also wasn't all that colourful for the club where their struggled to stay in the top 5 o the league table.
I think Liverpool are building something interesting this summer, after selling some of their first team players Jurgen Klopp have been active in this window and so far have been working on strengthening the midfield and attacking areas of the team. The squad is not yet at the level he would have loved it to be because of the nature of the market currently but I believe something will happen before the window closes, I am very optimistic about that.