I have the same issue. When I open my project in Xcode or switch Git branch, Xcode starts to resolve package dependencies even if Package.resolved file has not changed. When package resolving ends it starts to indexing project. It all takes about a minute or two and CPU usage is about 500%. So, when I switch branch I can't use Xcode because it freezing.

Done, FB9811175.

Does it use 100% for some time or just a spike? If just a spike, not an issue. It uses 90-100% always. Even If I create a new iOS project it still uses 100% CPU. So 100% may not be as much as it seems. This issue exists only in Xcode 13.2. So it is a bug.