As with many metaphysical and religious questions, Kant thinks they lie beyond our power to answer them. If you can't stand the frustration involved in accepting this, and insist on finding some more stable position which affords you peace of mind and intellectual self-complacency, then you will find Kant's position "problematic" in the sense that you can't bring yourself to accept it. You may try to kid yourself into accepting either some naturalistic deflationary answer to the problem or some dishonest supernaturalist answer.

Not only in order to act morally, but even to formulate theoretical questions, devise experiments, choose which ones to perform and what conclusions to draw from then - we must presuppose that we are free. That's the sense in which it is true that for Kant "we must assume we are free."

There is a lot in Adam Smith that reflects the insights of Rousseau and anticipates those of Marx.

There is a tradition of "modernist" theology arising out of post-Kantian thought - Fichte was the real father of it, but Schleiermacher and others also developed it - which might have more promise if it had greater influence on popular religion.

In the mid-1960s, as hard to believe as it may be now, choosing to go into academic philosophy was not an imprudent career choice. There were lots of academic jobs in philosophy then.

We can't coherently deny, or even decline to affirm, that we are free.

We can establish empirical criteria for free actions, and investigate human actions on the presupposition we are free.