High CPU usage on Mac is due to a macOS-specific QT5 problem with the Track/Playlist screen and scrolling/interacting with it when on a high resolution display (such as your Retina screen on your MacBook) - you should find that CPU usage will drop and performance will noticeably improve if you resize your Strawberry window to something very small.
I did have an issue ticket raised on this issue on the Strawberry GitHub page, which was closed as it was deemed to be unresolvable under QT5, and I'm trying to get it reopened/looked at again, now that QT6 has been released (which may have a fix for this CPU usage/performance issue).
This is probably related to the same issue with high CPU as some others have experienced on macOS, while it works fine for others. Performance in in general is worse on macOS then on Linux and Windows.
Unfortunately there has not been much interest in contributing to Strawberry from the macOS community over the past 3 years Strawberry has been developed.
Your problem is unrelated to the above topic which is solved, so I suggest to open a new topic for your problem
All plugins in the Windows installer should be bundled, so if they suddenly disappear along with your music files, then I would suspect a hardware disk failure.
I'm getting a message the GStreamer plugin is missing but the link you used isn't working. Many of my music files were wiped out. I have them backed up but I don't know how to reload from backup. Can you help? Thank you.
@terrior In Tools / Settings / Behavior. "When double clicking a song will..", you can change "Never start playing" it to start playing.
It will then immediately play the song, although it will still be added to the playlist.