I can run it on the simulators, and directly on physical devices, but not on My Mac (Designed for iPad). The error is:

error: attach by pid ‘33190’ failed — attach failed (Not allowed to attach to process. Look in the console messages (Console.app), near the debugserver entries, when the attach failed. The subsystem that denied the attach permission will likely have logged an informative message about why it was denied.)

Checked the log and this is what I found:

error 12:44:36.527139-0500 mdbulkimport could not make proxies from uuids in optimized path! Error Domain=NSOSStatusErrorDomain Code=-10814 “Unable to find this application extension record in the Launch Services database.” UserInfo={_LSFunction=, _LSLine=679, NSDebugDescription=Unable to find this application extension record in the Launch Services database., SK=, IS=0}

error 12:44:36.527174-0500 mdbulkimport Using expensive fallback path for obtaining plugin proxies from install notifications. This process should be entitled to use the LS database.

default 12:44:36.529748-0500 debugserver [LaunchAttach] (32518) about to task_for_pid(32517)

default 12:44:36.529778-0500 kernel macOSTaskPolicy: (com.apple.debugserver) may not get the task control port of (Piano Motifs) (pid: 32517): (Piano Motifs) is hardened, (Piano Motifs) doesn’t have get-task-allow, (com.apple.debugserver) is a declared debugger(com.apple.debugserver) is not a declared read-only debugger

error 12:44:36.529795-0500 debugserver error: [LaunchAttach] MachTask::TaskPortForProcessID task_for_pid(32517) failed: ::task_for_pid ( target_tport = 0x0203, pid = 32517, &task ) => err = 0x00000005 ((os/kern) failure)

So the issue seems to be not finding the application’s extension record in the Launch Services database. How is this problem solved?