Most clubs have debt. Forest have a debt of £60m which is repayable upon the departure of the chairman. They don't have a lot of cash to spend to start off with and if they get taken over and the new owners can't support the debt. You could struggle.
If you are interested in playing in a league away from England, I would suggest you take Beşiktaş. They have good players on a high wage budget so it would be challenging to lower that. Also, the club has around 200M Euros of debt but with the success you would achieve you can easily level that off. Qualifying to the Champions League will help you a lot. So yes, I think Beşiktaş would be a great challenge for you.