There is a room in football for those who aren't elite in both technique and physique, actually those who are elite in both aspects are usually the very very best, the top 5-10 players in their position
Eric is actually same height as
Umtiti and is one kg heavier, and no one ever has accused Umtiti of being weak.
He is 20 years old player, it is normal he won't be a bully yet, and there is enough room for him to grow there.
People keep talking about Bayern and Groetzke, but truth is we always helped our players to reach their best shape as long as they were willing to work in it (so, guys like Dembele were hopeless case). Players like Neymar & Messi werehelped tremendously by the club.
I remember when Neymar 1st arrived we made a program for him to add few KGs and his doctors in Brazil were mad and thought we will slow him down, but at the end we were right.
Back to Eric, I think he can be relatively strong and dependable in couple of years tnh. He will never be the most athletic but teams can survive with one of those. You don't need the best player for each position to win, sometimes you can just count on some players who are closer to average (for big club standards) than elite.
He is a 20 year old who had the faith of Pep, Lucho & Koeman beside every youth coach in Spain, the opposite of Puig for example.
He is a young free agent signing that who is still a project, whom we will have to rely on more than we should because we are broke, even if he turned into a good 3rd CB it is a win