Also seeing a similar issue. Noticed my MacBook Pro M1 (2020) was getting ridiculously hot, saw one SpringBoard process and two diagnosticsd processes each taking between 70%-103%. I'm running macOS 14.0 Beta (23A5301h) and Xcode Version 15.0 beta 5 (15A5209g), and had the Simulator open.
Console shows a near constant spamming of the following messages from SpringBoard:
default 12:42:48.635344-0500 SpringBoard [0x1363526c0] invalidated on xpc_connection_cancel()
default 12:42:48.635365-0500 SpringBoard [0x1363526c0] activating connection: mach=false listener=false peer=true name=com.apple.systemstatus.peer.0x1363526c0
Closing my Simulator was the only thing that got it chill out.