Closing deals as an unfunded sponsor

I am interested to learn peoples experiences in working with family offices and PE firms in order to close deals as an independent sponsor (unfunded).

I understand that there are offices which provide both equity and senior debt to independent sponsors and in return, the sponsor receives a closing fee and ongoing management fees.

I have heard stories where Independent Sponsors have multiple LOIs signed but could not close any of the transactions due to the appetite, or lack there of, from the various offices.

How hard is it to get these deals done? What have peoples experiences been?