I'm having the same issue.
App works fine when launched from Xcode, and even works fine when launched from Xcode as a release build. But when installed via Testflight, we get an immediate crash.
Here is the log:
Date/Time: 2021-12-08 13:29:31.3655 -0500
Launch Time: 2021-12-08 13:29:31.3603 -0500
OS Version: iPhone OS 15.1 (19B74)
Release Type: User
Baseband Version: 4.01.01
Report Version: 104
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Termination Details: (terminated at launch; ignore backtrace)
Triggered by Thread: 0
Thread 0 Crashed:
0 dyld 0x000000010519c198 __abort_with_payload + 8
1 dyld 0x00000001051a1d5c abort_with_payload_wrapper_internal + 104 (terminate_with_reason.c:102)
2 dyld 0x00000001051a1d90 abort_with_payload + 16 (terminate_with_reason.c:124)
3 dyld 0x00000001051722b4 dyld4::halt(char const*) + 328 (DyldProcessConfig.cpp:2046)
4 dyld 0x000000010516f578 dyld4::prepare(dyld4::APIs&, dyld3::MachOAnalyzer const*) + 3280 (dyldMain.cpp:0)
5 dyld 0x000000010516da04 start + 488 (dyldMain.cpp:869)
Thread 0 crashed with ARM Thread State (64-bit):
x0: 0x0000000000000006 x1: 0x0000000000000001 x2: 0x000000016b872d80 x3: 0x0000000000000098
x4: 0x000000016b872980 x5: 0x0000000000000000 x6: 0x0000000000000000 x7: 0x0000000000000000
x8: 0x0000000000000020 x9: 0x0000000000000009 x10: 0x0000000000000001 x11: 0x000000000000000a
x12: 0x0000000000000000 x13: 0x0000000000000036 x14: 0x00000002159ac609 x15: 0x0000000000000000
x16: 0x0000000000000209 x17: 0x0000000105196830 x18: 0x0000000000000000 x19: 0x0000000000000000
x20: 0x000000016b872980 x21: 0x0000000000000098 x22: 0x000000016b872d80 x23: 0x0000000000000001
x24: 0x0000000000000006 x25: 0x000000016b873758 x26: 0x0000000000000001 x27: 0x0000000000000000
x28: 0x0000000000000000 fp: 0x000000016b872950 lr: 0x00000001051a1d5c
sp: 0x000000016b872910 pc: 0x000000010519c198 cpsr: 0x0
esr: 0x56000080 Address size fault
Binary Images:
0x105154000 - 0x1051abfff dyld arm64e <c21dba379df93fc7b286734030e18bb1> /usr/lib/dyld
EOF
There is no stack trace available in the crash.
I am downloading 13.2RC to see if this fixes it and will update.