I don't know anything about difficult negotiations between Leipzig and Liverpool. But Liverpool are thinking two steps ahead all the time at the moment. Look at the Keita deal. I think it's unlikely that a young player like Lookman is going to acting up of his own accord. Seems a very quiet young man to me, certainly doesn't appear 'big' or even 'pig' headed. Therefore it's likely that he would be very heavily influenced by his agent. Agents are looking for the next move for their player all the time so that they can have another payday as soon as possible – just look at the agents fees that are paid when new players are signed. If it is the agent influencing him then highly likely agent is speaking to other clubs already, particularly clubs in England. I can't imagine why a player like Lookman would want to play in Germany – he is regarded as one of the best young England talents and it's less likely he will get England recognition if he is in Germany. It doesn't make sense for him to go there. If he wants to prove himself, why not just stay in the premiership and show how good you are. Therefore any move to Germany must be short-term. If this move to Leipzig is a stepping stone on a move somewhere else then who is it that Lookman is hoping to play for?
It's widely reported the negotiations between Rangnick and Liverpool were strained. Rang nick is a ruthless operator and I have to say I'd be very surprised to see him doing anyone a favour, never mind Liverpool.
I don't doubt the lad if influenced by his agent. I'm not sure what that has to do with a conspiracy between Liverpool/Leipzig though. 2+2 don't equal 23.
Likewise it seems very clear why the player would want to play in Germany, it's probably the best league in the world for giving young players an opportunity with a high emphasis from top to bottom about development of young players and coaching. You've seen lots of young players make the move and more will follow. Add in Leipzig are very much at the vanguard of this, and Lookman clearly had a positive time on loan there, an opportunity to play in European competition and you can see why this would be appealing.
Finally I have little doubt as to why Liverpool would want to buy him. Ultimately every player has a price and I suspect Lookman's will be too high for Liverpool.