This one sounds harder than it actually is. Simply set up a Player Career with an Icon like Beckham or Ronaldo and choose a top team on easiest settings. I took Real Madrid.
Then you can simulate trough the entire season, checking if the team qualifies for KO-matches and winnig on aggregate.
Dont forget to make a save before every UCL-match from february to be able to quit out and load if something goes wrong.
If done correctly and with a little bit of luck you should have it after about 15 minutes. You dont even need to play any game or even be in the squad. Your team simply needs to win the UCL-final.
Edit: As Neo Yggdrasill mentioned the Womens Champions League does not count as a continental club competition for this achievement. So trying to make things shorter while using a woman team unfortunately fails.