OK, at least I can answer my own question regarding responding to telegram_command events. I had just a group chat_id (negative number) in my telegram_bot configuration, that wasn’t working to receive command, but when I added my user id as a chat_id, that allowed the above testmessage automation to work, it would seem the commands are validated by user, not group chat. Example:
telegram_bot:
- platform: polling
api_key: "ABC:XYZ"
allowed_chat_ids:
- -XXXXX # group chat id with my bot - not good enough for /commands
- YYYYYY # my user id - required for accepting /commands reasonable, but directions unclear