I have LaunchDaemon plist launching a x86_64 daemon, which worked so far on my M1 Mac mini running Big Sur, but right after the reboot from upgrading to macOS Monterey, I see error launching with EBADARCH error, but when I load the same plist by hand it worked.
2021-10-27 10:23:15.602649 (system/com.[redacted] [530]) : Could not find and/or execute program specified by service: 86: Bad CPU type in executable:
2021-10-27 10:23:15.602661 (system/com.[redacted] [530]) : Service could not initialize: posix_spawn([redacted]) EBADARCH error: 0x6f: Invalid or missing Program/ProgramArguments
2021-10-27 10:23:15.602666 (system/com.[redacted] [530]) : initialization failure: 21A559: xpcproxy + 23196 [815][D33C7462-5256-38E5-AFD4-A1FF694581F3]: 0x6f
2021-10-27 10:23:15.602668 (system/com.[redacted] [530]) : Service setup event to handle failure and will not launch until it fires.
2021-10-27 10:23:15.602671 (system/com.[redacted] [530]) : Missing executable detected. Job: 'com.[redacted]' Executable: '[redacted]'