Termux may be unstable on Android 12+. Android OS will kill any (phantom) processes greater than 32 (limit is for all apps combined) and also kill any processes using excessive CPU. You may get [Process completed (signal 9) - press Enter] message in the terminal without actually exiting the shell process yourself. Check the related issue #2366, issue tracker, gist with details and this TLDR comment on how to disable trimming of phantom processes.

Deactivation Instructions (ADB):
On an ADB console, paste the following commands on the following order:
adb shell "/system/bin/device_config set_sync_disabled_for_tests persistent"
adb shell "/system/bin/device_config put activity_manager max_phantom_processes 2147483647"
adb shell settings put global settings_enable_monitor_phantom_procs false