Freedom of religion is anatomically equivalent to freedom from religion; which is to say, there are no state-sponsored consequences resulting from your choice of religion or lack thereof. Whether that results in more or less ‘freedom’ for you really depends on you and not on the state.
Religion, on the other hand, is generally just acceptance of a standardized set of spiritual beliefs. Christians are people who accept that Jesus is their personal conduit to salvation. Catholics are people who, while believing in the same god, accept that the Church is their conduit to salvation. To be part of a religion is largely to accept a preconfigured set of beliefs and make them your own.
It is belief itself which destroys freedom. If you “believe” that a thing is valuable, then you no longer have the freedom to assist or ignore an attack on it. If you believe that thunderstorms are troublesome for aircraft, then you no longer have the freedom to fly through hurricanes. If you believe that Jesus is your main man, then you no longer have the freedom to sacrifice human beings to your idols. All of these, of course, being freedoms that you give up in order to retain your beliefs and maintain an internally self-consistent mindset.
The question really is; if there exists truth out there somewhere, and you find it and believe it, and it constrains your actions in some manner… are you more free or less free?