20 games is not much. Surely the purpose of the loan card is to "try before you buy/commit to the SBC." It might be the only way some people get to use some of the icons.
Do not allow them to be used in the weekend league but do not make them 50k+
No one in their right mind would do that SBC.
You could even decrease the amount of games to 7/10 if needs be.
They should be priced around 10-15k. Maybe top tier icons (maldini, Gullit etc) 20/25k. That would also help to take coins out of the game compared to few doing the loans for any of those who cost 50k+ Even some average icon loans have cost that much.
This extends to POTM/other player SBCs.