Update :
The performance issue when zooming over trimmed parts only occurs when HiDPI is Disabled.
When HiDPI is Enabled, this specific part of the issue doesn’t trigger anymore, and furthermore, it seems like the waveform stays in the interpolated state (smooth), so the first few parts of the first post become irrelevant.
However, even if HiDPI is Enabled and the waveform seem to stay smooth, the performance issue that is triggered by selecting and displaying multiple Events at once in the Editor and editing them in the project window, will keep occurring, regardless of the HiDPI setting.
In any case, any testing that you may undertake must first be done with HiDPI Disabled, which was the current setting at the time my first post was written and the videos recorded.
Here are some videos showing the issue.
Everything is still explained in the first post.
(Videos without Interpolate are below, so you can compare)
Interpolate = ENABLED :
Interpolate = DISABLED :