@RaelIAK,
The resume report showed that in Sigil in Qt6 code inside the macOS libFontRegistry.dylib was looping in the process of building up a cache of your fonts to find a fallback font to the one requested by Qt. It never seems to finish, it seems to get stuck in an infinite loop.
Have you installed third party fonts in your system?
Have you removed any Apple supplied fonts on your system?
Do you have an unusually large number of fonts on your system?
Please Try running the Mac Font Utility tool and letting it check for broken or missing fonts.
And when you renamed sigil.ini did you remember to also rename the sigil_v6.ini as I showed earlier. Both must be renamed in order to start Sigil with fresh settings.
Update:
And your resume report shows you also have a strange third party Adobe Sync product running simultaneously that might be related to the issue as it is a service that syncs fonts (files and other assets) from your mac to the Adobe Cloud Services.
My guess is the process is taking forever as Adobe Sync is adding/removing fonts from the Adobe cloud to your mac dynamically.
So turn that Adobe Sync app completely off and then try running Sigil. My guess is that is that Adobe Sync is the real problem.
In newer versions of macOS the ACCFinderSync process is disabled and removed automatically by MacOS when updating.
Process: ACCFinderSync [536]
UUID: 194CF9DF-3361-313C-80A7-511745674CE6
Path: /Applications/Utilities/Adobe Sync/*/Core Sync.app/Contents/PlugIns/ACCFinderSync.appex/Contents/MacOS/ACCFinderSync
Identifier: com.adobe.accmac.ACCFinderSync
You might want to first try launching Sigil after pausing Adobe Sync. The instructions are here:
https://helpx.adobe.com/ca/creative-...c-options.html
Be aware that really turning off Adobe Sync can be quite hard as it keeps reinstalling itself.
I would do a google search on how to remove it. Here is one blog talking about how hard it is to remove.
https://www.ctrl.blog/entry/how-to-d...loud-sync.html
After reading all the anger by customers of Adobe over the inability to turnoff this "feature" you may want remove it completely as it is acting like malware for many people.