Having only two possible opponents also makes draws much more boring than they should be. It also makes it more dull knowing who you will play in each round. I would just do a new draw each round with the highest remaining teams seeded and the lowest remaining seeds not seeded. Pretty simple and makes it worth finishing, say, third rather than fourth as it could affect your seeding later on in the tournament.
Genuinely mental that anyone would be more excited by playing Man U than Real Madrid, Barcelona or even fairly recent opponents like Bayern Munich or Juventus, tbh.
