Working on XCode 13.1, Monterey - confirming saw the issue where SourceKitService & swift-frontend memory usage would each explode to around 40GB.
I saw this issue fairly quickly - within minutes - of using GeometryReader in a project. After going through above thread, I decide to remove the code using GeometryReader, force quit above services, closed and re-opened XCode.
So far, I do not see any spike in memory in the above services. SourceKitService is at about 70MB, XCode at about 1.11 GB. Launched app on device and so far, XCode and system is stable with above usage.
Would love to know what the issue is here.