It just needs to be big enough to trigger the timeline. This one was around 34M, had sold 3 players for 20 in 2029-2030 and no crash.
17 january 2026
"Record sale"
"Francisco meixedo was Bought by Barcelona for 750m€, record sale for the club." Didnt make the game crash
Multiple free transfers till 2028 that appear in timeline didnt crash the game.
16 july 2027
Bought a player for 1.5M record fee, appears on timeline and no crash.
25 june 2028
Sold a player for 7.75M no crash and appears on timeline
14 June 2029
Sold idol for 14M no crash
2 july 2029
29.5M for 2 players I sold and no crash, record sales beaten.
Got some more transfers that didnt trigger the crash on timeline.