I rekon the stats probably back this up, but I don't think CW's BrexitBlades is really a thing. Certainly not in some deliberate 'no forins' way. I think, that in the first stint, HRH relied on CW's little black book. He had extensive knowledge of Champ, L1 and L2 players - his experience pre-United wouldn't have offered him deep international insight because of the budgets at his previous clubs.
Then, when we had money to play with in the first PL season(s), we still had a squad made up from Black Book acquisitions with contracts to honour and players that deserved a crack at the PL. This coupled with a not fit for purpose scouting / recruitment department - the On Field part of the club outpaced the Off Field side (still is arguably) - conspired to limit our international options IMO.
Then The Back Door Affair happened and we fast forward a few seasons. CW is back at the club and the club is going through massive off field changes and we, again, are in a situation where the On Field part of the club is outpacing the Off Field side. So, CW etc. are cutting their cloth accordingly. I fully believe that given the right insight, data and personality, CW will have no trouble recruiting from over seas. However, being cheap and non-domestic is not enough in and of itself. Which is exactly how it should be.