Cardiff will do just fine as a holding pattern for Bale.
Only a Welsh team will allow him to pick and choose his games. There’s no way he is up to playing Sat Tues Sat in the Championship.
In addition he will want to avoid playing in the two or three weeks before the World Cup to make sure he doesn’t get injured.
Because this World Cup is unique - games start 8 days after the last round of EPL/Champ games. Get an injury that weekend and you have no time to recover.
So he might well do some sort of deal with Cardiff until the World Cup. But he probably won’t play more than half a dozen games for them, with most of them at home to boost gates.