Q: Gears are difficult to change - 2000 BMW 328Ci

Upon purchasing this pre-owned car, I was aware it had a flex disc issue. While shifting, there was a bit of noise. Also, when the engine starts revving around 3200 RPM, the gear gets stuck and it becomes difficult to shift out of any gear. I had this problem while I was driving at the highway. I put it in fifth gear with the 3400 RPM and I attempted to downshift but it was very difficult to change gears at this point. I think the clutch is working fine as it enables the RPMs to decrease. It's as if the gears don't have dog clutches between them. What might be causing gears to get stuck like that?