There's a really awful playback issue on my machine that causes delays of up to several seconds when playing back audio.

For some reason, when opening a project saved in Audacity 3.4.2 in 3.3.3, all of the mono audio tracks were converted tot left channel stereo. The fix was:

• pick a track and Make Stereo Track. This will take this track and the track below and make them stereo.
• Split Stereo to Mono then takes both tracks and marks the mono again.