You do understand that a team from small country will have more revenue due to no competition thus making him able to create a better team that the guy in the big league because he wins everything nomatter what -> Fan survey is always maxxed.
And the problem is?
If he/she doesn't improve the team on TL and thus not competing with major clubs, you shouldn't bother.
If such a team hits TL and compete with major clubs' bids it will pay more in salaries and if the team would keep doing this the "problem" would balance itself.
If such a team play in BBB, he/she would need those players. Since manager can't choose a country to play in, he shouldn' be fined for where he/she plays. If he plays with bots, inferior teams in top league it reduces the fun a bit, so it is only legitimate to get a slight advantage to compete in BBB, actually face a real competition somewhere.
And I think you are wrong because there are surely small, middle-sized countries where several team seriously competes in top division. How is supposed to be fair for them?