Mourinho got great opportunities at Manchester United, but this did not lead to anything, so it may not always give the expected result. I think that he will receive some kind of funding, since for two seasons in a row he took Roma to the Euro Cup finals, but this funding would be much larger if Roma won the El final and got a place in the Champions League. By the way, Mourinho decided to stay at Roma, so apparently he still got some kind of budget to strengthen the team.
I haven't seen any update on Mourinho's decision. Are you sure that his decision is final? Because a few days ago I read that he would be okay to stay longer but he said that he would inform the board if he gets an offer from PSG as well. This must be still the same now. Because PSG are about to sack Galtier and Mourinho is a strong candidate for now.
If PSG make an offer for Mourinho then I'm not so sure about if he would like to stay with Roma instead. Because while he can win titles easier with PSG why would he want to continue with Roma and struggle more, right?