Same experience with Pro. My trick is to attach the codebase as a txt file to 5-10 different GPT 5.2 Thinking chats, paste in the specs, and then get hard work

Same experience with Pro. My trick is to attach the codebase as a txt file to 5-10 different GPT 5.2 Thinking chats, paste in the specs, and then get hard work done there, then just copy paste the final task list into codex to lower codex usage.