Real Madrid are the biggest club in the world, there is no doubt about that I think. As big as they are though, they will never get Trent Alexander Arnold to leave Liverpool. He is born and bred in the city, Liverpool is his team.
Besides £70,000,000 wouldn’t even buy his left leg

No way he goes to Real Madrid and I would take bets on that.
Real Madrid is looking for a successor to Dani Carvajal, so the Merengues' interest in planning for the club to reinforce its right-back position is clear. In fact I read that they were offering 80 million euros to Liverpool for Trent Alexander-Arnold.... not that 10 million makes a difference, but I also don't believe that the player will leave Liverpool.
Quite the opposite... Trent Alexander-Arnold also reveals that he is very satisfied at Liverpool and revealed that he is shaping his game to adapt to his new hybrid role in the team since the end of last season in which he has been deployed in one position which combines right-back and midfield. Liverpool's formation has improved greatly since that adjustment, with Alexander-Arnold's ability to consistently dictate play from central areas a key factor.
Anyway... Liverpool need Trent Alexander-Arnold and won't sell him
I think Real Madrid might find some difficulty in actually getting a player like him. It is going to be something like when Barcelona lost Dani Alves. They were not being able to find a really good right back. Actually, I will say that they have not found a really good right back since then. Whoever came didn't do a very good job, to be honest. But the thing is Real Madrid is not like Barcelona. Real Madrid has a good amount of money. If they throw around enough money, I think they will be able to get a good player. But they might not get a really good replacement instantly.