Roberto is better offensively than Semedo which is why he starts. I don't really want Semedo but I also don't know if Aarons will be good enough for us in the near future. He's high rated but that's probably mainly due to his nationality and his performances last season in the championship. He hasn't impressed this season and nothing about him stands out. He's a jack of all trades, average at every department. He doesn't have a redeeming quality like Walker has his physicality, TAA has his crosses or Wan Bissaka has his tackling. He also looks quite short and weak, there's no way he's 178cm
I'd go for Atal as Walker backup, he's very similar to Cancelo but maybe even better going forward. Then try to fill HG quotas in other ways, maybe getting Aké as Otamendi's replacement