GPT for Sheets is executing too slowly & running into time-out errors ... any recs?

Hi all -
I’ve built a great model to generate personalized email drip campaigns to podcast hosts based off of recent episode information.

The issue is that I really like the gpt4 results, but the commands are timing out. The responses are also generally too long, but when I tone down the Max response size, it no longer generates complete emails … they get cut-off.

Any ideas?