It's actually going to be four countries, not just one. Uruguay, Argentina, Chile, and Paraguay are bidding for the 2030 World Cup.
If they actually get it, it would be an awkward South American qualification. There are 10 teams, and from the next world cup there will be 6 directly qualified teams with one going to playoffs.
With 4 South American countries qualified as hosts, and 6 directly qualifying, that would mean the whole continent would qualify for that world cup, without a single qualifying match needed.
What a load of BS?
If the joint bid from Uruguay–Argentina–Chile–Paraguay wins the hosting rights for FIFA World Cup 2030, then a total of only 6 teams will participate in that tournament from the CONMEBOL region. Out of the 48 participants, 6 are supposed to come from this confederation. And if they win hosting rights, then 4 out of the 6 slots will be reserved for the hosts, while the non-hosting countries within CONMEBOL will participate in the qualifier tournament from which the remaining 2 slots will be decided. So let's be clear about it. A total of 6 teams will be from CONMEBOL, and not 10 as you are claiming.