You've left out quite a bit of important information.

If you're using PD365 (the subscription version), there's no way to roll back to an earlier version unless you report the issue to Cyberlink tech support and they determine that's the best course of action. You can reach them here.

If instead you're using PD21 (lifetime license), you can uninstall it and then install it again using the original installer. Then simply don't install the latest patch.

In PD365, I haven't noticed any changes in the behavior of transistions. A screenshot or screen recording showing the issue would be very helpful, as there are a number of other reasons why a transition may not affect the timeline audio.

As for the freezing/glitches, see if FAQ #7 might be relevant. It would also help to see the DxDiag test results as described in the Read Me Before Posting guide.