So...im Portuguese, although i dont follow Sporting's day to day stuff, they turned their situation as a spursy - also ran - club around by bringing Ruben Amorim as a coach. After that apparently they poached some scouts from a mid table team that recruits well and found some (semi) hidden gems like gyokeres, hjulmand, diomande and others.
To me, that seems like scouting doing a good job but city's board surely know better and saw something in Viana that they really liked. Now, sporting is a big club but they have to operate in the margins of the market, while we will be expected to sign big name players like wirtz, musiala, rodrygo, etc.. The job is totally different, and he is unproven at that level, so we will see
I know that you will not like to read this but Amorim and Viana have a symbiotic relationship by most accounts and yeah, it might mean pep either leaves this or next season. I hope im wrong but...