Captain Hindsight : Fix one transfer mistake per summer

This is news to me. Did Haaland want to come to us, but we said we can only give him Martial's backup role?
Pretty sure it was because we wouldn't agree to putting a buy-out clause in his contract
 
Swap one of the players we signed, for a player our rival/other team signed in the same transfer window for the same fee or less. All the other transfers summer remain the same.
Thread inspired by @BrilliantOrange who pointed out all the other CBs that moved for less money in the same summer we signed Lindelof for £40m.

Summer 2013: Christian Eriksen instead of Marouane Fellaini. Automatically make Spurs (one of our top 4 rivals) weaker as well. for years to come.
Summer 2014: Toni Kroos instead of Angel Di Maria. feck Louis Van Gaal's veto.
Summer 2015 - Kante instead of Morgan Schneiderlin. Nobody had even heard of Kante apart from Leicester who signed him for £6m. He goes on to star in two consecutive title wins for Leicester and Chelsea. Schneiderlin drifts into nothing. We might have had an outside shot at the title Leicester won because the points total was that low - even with our disgraceful goals total which I haven't addressed at all so far.
Summer 2016: Sign Mane instead of Mkhitaryan.
Summer 2017: Skriniar instead of Lindelof
Summer 2018 : Rodri instead of Fred (moved to Atletico that summer for £20m).
Summer 2019 :
Summer 2020 :
Summer 2021 :

Obviously we still look like a complete mess, but how much better could we have been?

Could arguably go back even further - I think a fair chunk of the damage was done during the 'no value in the market' years when we missed out on the likes of Hazard, Aguero, D. Silva, Kompany etc...because we weren't willing (or able) to spend.

From what we have above

2013 - Fernandinho (Shakhtar - City - £30m) over Fellaini (Everton - Utd - £27.5m)
2014 - Alexis Sanchez (Barcelona - Arsenal - £35m) over Angel di Maria (Real Madrid - United - £59.7m)
2015 - Kevin de Bruyne (Wolfsburg - City - £55m) over Memphis Depay (PSV Eindhoven - United - £31m)
2016 - Sadio Mane (Southampton - Liverpool - £34m) over Henrikh Mkhitaryan (Borussia Dortmund - United - £28m)
2017 - Antonio Rudiger (Roma - Chelsea - £29m) over Victor Lindelof (Benfica - United - £31m)
2018 - Allisson (Roma - Liverpool - £56m) over Fred (Shakhtar - United - £47m)
2019 - Keiran Trippier (Tottenham - £20m - Atletico Madrid) over Aaron Wan-Bissaka (Palace - United - £50m)
2020 - Thiago (Bayern Munich - £20m - Liverpool) over Donny van de Beek (Ajax - United - £35m)
2021 - Marc Cucarella (Getafe - £15m- Brighton) over Cristiano Ronaldo (Juventus - United - £12.5m)
 
Lewandoski in 2012 instead of Van Persie. Both are great strikers, but Robert will still be with us this season, scoring hat-trick.

ANY choice but Telles & AWB, Maguire, Lindelof. I can accept the mistake on Bailly because of this athleticism. The others are pure incompetence on the scouts.