Out of interest what league are you managing in?
To build a nation, you need to aim for a good continental run season after season, that will really help. Try loaning out or selling your fringe players to your league rivals, and as you are doing try to buy players from them to add to their funds.
I actually started a new save in Latvia last week. Got to the Europa Conference semis in my first season and the club, league and nation ranking went up a fair few places. The rest of the league is awful but overtime I should be able to make it more competitive. Did the same think in Croatia on last year's edition and ended up making the league the 3rd best in Europe after 11/12 seasons.
It takes time and patience. Good luck;)