1) Neither.
2) Yes, I use pay as you go from OpenAI and Anthropic.
3) OpenCode
4) No
5) No
I use OpenCode to update my Home Assistant automations. Home Assistant also does two lightweight checks a day using gpt-5-luna (Look at this photo is the pool cover on or off?). I also use OpenCode for a few other small basic tasks.
This is me personally. At work I have a ChatGPT sub an a, seemingly limitless (I don't use it much tho) OpenAI API key.